On the morning of 22 February 1847 the Americans were ready for the Battle of Buena Vista. Fewer than 5,000 men, most of them ill-trained volunteers, were deployed mostly east of the road near the larger spur, La Angostura, where the artillery had been positioned to command the road. The Mexican army was more than three times as numerous as the American force, and its advance guard arrived at about 11.00. Santa Anna saw that the terrain did not suit his cavalry, but his demand for an American surrender was curtly refused.
Santa Anna placed his artillery on the road and on the higher ground to the east of the road, and despatched a force of light infantry to the east on an enveloping movement. The Mexicans started the battle at about 15.00 with their artillery, but there was more manoeuvring than fighting for the rest of the day as the two sides sought to gain the more advantageous positions on the spurs commanding the battlefield. The Mexicans generally came off better in this jockeying for position, and the skirmishing ended at nightfall.
The battle proper was fought on February 23. The Mexicans started with an attack to the west of the road, but the defeat of this assault by American infantry and artillery ended all efforts in this sector. On the plain below the spurs Santa Anna now committed his main attack, a sterling effort by two divisions from the Southern Plateau against the Americans holding the access to the Central Plateau. The attack was checked by an Indiana regiment supported by three guns, but when the regimental commander ordered a retreat the men broke and ran, panicking the flanking regiments into similar action. The Mexican advance across the American front and against the American left wing on the Central Plateau was threatening to cause an American rout by 09.00, but at this point Taylor returned from Saltillo with some dragoons and Colonel Jefferson Davis’s 1st Mississippi Regiment. These fell on the Mexican cavalry trying to turn the American flank on the North Plateau, and when joined by Major Braxton Bragg’s battery of artillery and the 2nd Kentucky Regiment started to push the Mexicans back.
With a major American victory almost in sight, Santa Anna committed his reserve division, which had been waiting in the ravine between the Southern and Central Plateaux and now advanced in two columns. The left-hand column descended on the three regiments (one Kentucky and two Illinois) of the American right wing and pushed them back toward the road. The right-hand column attacked the American centre, and a major US defeat seemed on the cards. At this point Bragg’s and Sherman’s batteries left the fight against the Mexican right wing on the Northern Plateau, where the Mexicans were starting to fall back, and galloped over to the Central Plateau to support the American centre and left wing against Santa Anna’s reserve. Soon after this the 1st Mississippi and 3rd Indiana Regiments crossed the ravine from the Northern Plateau and struck the Mexican main body in flank. Meanwhile the Mexican cavalry launched on its eastward sweep right at the beginning of the battle had been repulsed outside Saltillo by the US rear guard.
Santa Anna pulled his army back to the road below the Central and Southern Plateaux as night started to fall, and took stock of his position. Realising that he had lost between 1,500 and 2,000 men he decided to retreat to San Luis Potosi. The Americans had won the bloodiest battle of the American-Mexican War, in the process suffering casualties of 264 killed, 450 wounded and 26 missing. The American victory ended all chance of a Mexican descent on the lower reaches of the Rio Grande river area.
Kearny’s and Doniphan’s Expeditions
The USA had long coveted the Mexican province of Upper California, and the area had been in considerable turmoil for some time as American settlers agitated for US annexation. The trouble in the region became worse in 1842, when Commodore Thomas ap C. Jones of the US Navy landed a force at Monterey. The action was later disavowed by the US government. At the outbreak of the American-Mexican War the American settlers of the region were encouraged to revolt by a US Army captain, John C. Fremont, who was leading a surveying expedition in the west.
In June 1846 a flotilla of US Navy ships commanded by Commodore John D. Sloat reached Upper Californian waters after a passage from the east coast of the USA round Cape Horn, and set about taking most of the major towns along the coast. Monterey was the first of these on 7 July, and other places taken by the US Navy included Yerba Buena (now San Francisco) on 9 July, San Diego on 29 July, Santa Barbara on 4 August, Los Angeles on 13 August, and Sonoma. In the seizure of all but San Diego, bands of American settlers played an important part. The expansion of these American footholds was undertaken by Sloat’s successor, Commodore Robert B. Stockton, and Fremont was then named governor of California. This was intolerable to most of the Mexican population, which rose against the Americans and controlled most of the province.
All this was unknown to Kearny when his expedition to take New Mexico and California departed from Fort Leavenworth, Kansas, on 29 June 1846. The expedition crossed into Mexican territory on 28 July after leaving Bent’s Fort on the upper reaches of the Arkansas river, and moved through Las Vegas on 15 August to reach Santa Fe on 18 August. With 1,700 men, Kearny had established complete US control over New Mexico. In Santa Fe Kearny learned of the pacification of California, and decided to leave most of his force as garrison for New Mexico before pushing forward again.
Thus it was with only 120 dragoons that Kearny left Santa Fe on 25 September, heading for south-western California. This small party passed south along the upper reaches of the Rio Grande to Albuquerque and Socorro, where Kearny struck out to the south-west and the headwaters of the Gila river. The Americans reached the junction of the Gila and Colorado rivers on November 22, and heard of the Mexican uprisings against American rule in California. At this point Kearny found his advance checked by a force of 500 Mexican cavalry. In the Battle of San Pascual, fought on 6 December, Kearny gained a tactical success against the Mexicans but failed to dislodge them from his route to San Diego. Kearny managed to make contact with Stockton’s naval force, which on 10 December sent out a detachment of sailors and marines to help the small group of dragoons. Kearny finally reached San Diego on 12 December, and American possession of California was assured on 9 January 1847 in the Battle of San Gabriel. In this engagement outside Los Angeles the combined army and navy force routed the main Mexican strength in the region, and Mexican resistance quickly crumbled.
Kearny’s strength was considerably bolstered on 29 January when his wagon train and a battalion of infantry under Major Philip St George Cooke arrived after taking a more northerly route through the Rocky Mountains. Kearny’s achievement was enormous, for the main part of the expedition had been over extremely difficult deserts and mountains.
Doniphan’s expedition was an offshoot of Kearny’s expedition, and was designed to pacify the region along the upper reaches of the Rio Grande. With 850 mounted riflemen, all Missouri volunteers, Doniphan left Santa Fe on 12 December 1846 and moved down the Rio Grande to El Paso, which the Americans reached on 5 February 1847. Here they left the river and headed south toward Chihuahua. North of this town the Americans met and defeated a far larger Mexican force in the Battle of the Sacramento River, which was fought on 28 February. The Americans suffered only seven casualties to the Mexicans’ 600, and were left in effective control of the central part of northern Mexico.
Doniphan remained at Chihuahua between 1 March and April 28, and then moved south-east toward Parras and Saltillo, where he linked with Taylor’s force on 21 May. It had been an extraordinary achievement, for the Americans had moved through 2,000 (3220 km) or more miles of desperately inhospitable country never before crossed by a major military force.
The Central Mexican Campaign
Scott’s invasion force assembled off Lobos Island, about 50 miles (80 km) to the south of Tampico, and sailed for Vera Cruz on 2 March 1847 with an escort of warships under Commodore David Connor. This was to be the first major amphibious operation in US military history, and involved 13,660 men including 5,741 regulars. Off Vera Cruz the convoy of transports linked with Commodore Matthew C. Perry’s US Navy warships that were blockading the Mexican port. Scott decided to undertake a personal reconnaissance of possible landing areas, and the small boat in which he and other officers were embarked was very nearly sunk by artillery firing from the fort on the island of San Juan de Ulua opposite Vera Cruz. This could have altered the course of the American-Mexican War, but could also have affected the outcome of the Civil War for among the more junior officers present were four men (Pierre G. T. Beauregard, Joseph E. Johnston, Robert E. Lee and George G. Meade) who all rose to very high command in that war.
Scott chose for the landing a beach about 3 miles (4.8 km) to the south of the city largely because it lay beyond the reach of the Mexican artillery. During the evening of 9 March about 10,000 men were ferried ashore in 65 surf boats that had been towed to Vera Cruz by steamboats. This force quickly moved inland without opposition from the Mexican garrison of 4,300 men inside Vera Cruz. The next step was the landing of stores and artillery, while horses were dropped overboard from the transports to swim to shore. The process was considerably slowed by heavy winds that arrived on 12 March and lasted for four days. By March 22 seven 10-in (254-mm) mortars had been located south of Vera Cruz.
The American bombardment of Vera Cruz started during the afternoon of 22 March, and the Mexicans replied with fire from the fort and city itself. Scott soon found that the mortars were not as effective as he had hoped, and was compelled to ask for naval aid. Perry landed six guns, in the form of three shot-firing 32-pounder and three shell-firing 8-in (203-mm) weapons, and these soon breached the walls of Vera Cruz. On 27 March Vera Cruz was surrendered by the Mexicans, who had suffered 180 casualties (including 100 civilians) to the Americans’ 82 losses.
Fear of disease
Scott was fearful about the onset of yellow fever, a disease endemic in the region, and planned an immediate move with 8,500 men to Jalapa, about 75 miles (120 km) along the main road from Vera Cruz to Mexico City. Transport was difficult, and it was 8 April before there were adequate numbers of wagons and mules available for the advance. On that date the advance guard set out under the command of Brevet Major General David E. Twiggs, its strength including one battery of heavy artillery (24-pounder guns, 8-in howitzers and 10-in mortars) and another battery with mountain howitzers and rockets. These last were an Ordnance Department responsibility, and after launch from grooved stands were stabilised in flight by the spin imparted by angled vents in the tail. Also included in Twiggs’s 2,600-man strength was a single dragoon squadron.
Scott had warned Twiggs that Santa Anna was somewhere on the road ahead of him. Three days later, after an advance of some 30 miles (48 km), Twiggs learned that the Mexican army of 12,000 men was positioned across his line of advance at Cerro Gordo. Here the road ran through a defile, and Santa Anna had deployed his force to take best advantage of this feature. The main Mexican strength lay on its right wing, with batteries emplaced on the mountain spurs commanding the American left. Farther back, on the Mexicans’ left wing and positioned to deal with the right of any American advance, was more artillery on a high hill called El Telegrafico.
The Mexican guns opened fire in nice time to warn Twiggs of their presence before the american were in effective range, and the advance guard was halted. On 14 April Scott’s main force reached the advance guard, giving the American commander an overall strength of 8,500 men. A reconnaissance by Captain Robert E. Lee revealed that the area on the Mexicans’ extreme left, which Santa Ana believed to be impassable, could in fact be traversed and thus opened the possibility of outflanking the Mexicans. Heavy artillery had to be lowered by rope down into ravines and then hauled up again on the other side, but by 17 April an American detachment had been able to occupy a hill beyond El Telegrafico, and here they installed the rocket battery.
The Battle of Cerro Gordo
The Battle of Cerro Gordo began on 18 April. Santa Anna had learned at the last minute of the US move round his left flank, and had sought to protect this vulnerable sport with extra artillery. The battle itself was short and sharp, the Mexicans breaking and fleeing into the mountains after suffering some 1,000 casualties. The American casualty list of 417 included only 64 killed. The scale of the Mexican defeat is confirmed by the fact that the Americans also took 3,000 prisoners, about 40 guns and 4,000 small arms.
On the following day Scott moved forward to Jalapa, and with Mexico City now relatively close the campaign appeared all but over. Scott was faced with a considerable problem, however, for his army was in danger of losing much of its strength. The enlistment of the men in seven of his volunteer regiments was about to expire, and only a few could be persuaded to re-enlist. The departure of the time-expired men and a growing number of sick soon reduced Scott’s strength to a mere 5,820. Even so, during early May the Americans pushed forward to Mexico’s second largest city, Puebla. Fortunately for the Americans, the citizens of Puebla were against Santa Anna and the city surrendered peacefully to Brigadier General Worth’s advance guard on 15 May.
Scott decided to pause in Puebla until his strength had been increased by reinforcements moving up from Vera Cruz. By the middle of July the US strength had been more than doubled, but Scott still lingered as peace negotiations were under way. Santa Anna had been approached soon after his election for the second time as president, and agreed to discuss peace for a down payment of $10,000 and another $1 million when a peace treaty was ratified. Santa Anna pocketed the initial payment and then said that he could proceed no further since the Mexican congress had recently passed an act making it treasonable for any Mexican to deal with the Americans.
It was clear that military pressure would have to be applied, and for this purpose Scott had just fewer than 11,000 men. The only objective whose loss would exert the right type of pressure was Mexico City, but such a move would require Scott’s complete strength as Santa Anna was known to be concentrating his 30,000-man main strength for the defence of the capital. The US commander therefore made the dangerous, but ultimately right, decision to abandon his line of communications from Vera Cruz to Puebla so that all his effective strength would be available for the advance.
Leaving its sick and a small garrison in Puebla, Scott’s army pushed forward on 7 August in three divisions trailed by a 3-mile (4.8-km) column of wagons. The Americans met no opposition, and rightly concluded that Santa Anna was concentrating all his men for the defence of Mexico City. By 10 August the Americans had reached Ayotla, about 14 miles (22.5 km) from the Mexican capital. Here reconnaissance to the north-west revealed that the main road to the capital was barred by strong defensive positions centred on the fort at El Penon just to the south of Lake Texcuco.
Mexico City outflanked
Scott therefore decided to take the city from the west after a deep outflanking movement to the south round Lakes Chalco and Xochimilco. Scott hoped to follow this southerly route between the lakes and the mountains to their south, skirt round the south-west of the Pedregal lava bed, and then turn north to cross the Churubusco River and arrive on the western side of Mexico City.
By 17 August Scott’s 10,740-man army had reached San Augustin on the south-eastern tip of the Pedregal, which was 15 miles (24 km) wide and considered impassable. Again Lee found a way across this desperate area, and an advance guard under Brevet Major General Gideon J. Pillow was despatched, with support from Twiggs’s division, across the Pedregal on Lee’s mule path. Soon the Americans came under fire near Padierna from a Mexican force under General Valencia, whose 68-pounder howitzer completely outclassed the Americans’ light artillery. Checked by the Mexican artillery, and faced with the problem of Mexican reinforcements moving south from the capital, Scott committed an outflanking party to a difficult night march to debouch on the Mexicans’ right flank, and in the Battle of Contreras on 20 August the Americans attacked the Mexicans on the front and flank. The Mexicans were swept aside in only 17 minutes. American losses were 60 killed and wounded, while the Mexicans suffered the loss of 700 killed and 800 captured, the latter including four generals and two pieces of US artillery which had been lost in the Battle of Buena Vista.
The Americans had supplies left for only another three days and, in the hope of keeping the Mexicans off balance and thereby making rapid progress, Scott ordered an immediate pursuit. The wily Santa Anna had foreseen such an eventuality, and improvised a strong position outside the town of Churubusco. Here the bridge was strongly held, and a stone-built church and neighbouring convent had ben converted into a fort. The Americans arrived at about noon, and ran into a wall of musket and artillery fire. The Mexicans fought better than they had at any point in the campaign so far, and it was only in the middle of the afternoon, as the Mexicans began to run short of ammunition, that the Americans made any progress. Finally the Americans stormed the convent, and the Battle of Churubusco was over. In overall terms the day had been costly for both sides. The Americans had lost a total of 137 killed, 877 wounded and 38 missing. The Mexicans had suffered about 4,300 killed and wounded, 2,637 taken prisoner and about 3,000 missing.
The day had thus cost Santa Anna about one-third of his overall strength, and the defeats at Contreras and Churubusco were the pressure required to bring the Mexican leader back to negotiation. Santa Anna proposed a resumption of negotiations, and Scott countered with the offer of a short armistice, which Santa Ana accepted. For two weeks Mexican representatives talked with Nicholas P. Trist, the Department of State official who had arranged the initial $1 million deal with the Mexican leader. It then became clear that Santa Anna was negotiating in bad faith, using the time to rebuild his strength rather than reach an agreement. Scott halted the talks on 6 September and prepared to attack Mexico City.
The American strength was now about 8,000, while Santa Anna had about 15,000 men and the fortress of Chapultepec that commanded access to the western side of Mexico City. As a first step, on 8 September Scott’s army attacked and captured El Molino del Rey. The battle lasted right though the day, and at the cost of 116 killed and 655 wounded the Americans secured this collection of low stone buildings, including an old fort and cannon foundry, in the process killing or wounding 2,000 Mexicans, capturing another 600 and opening the way to Chapultepec about 900 yards (825 m) away.
After four days of preparation, Scott launched the Battle of Chapultepec on 13 September. After a barrage from their 24-pounder guns, the Americans attacked at about 08.00 in three columns. The central column advanced up the hill topped by the fortress. The Americans soon reached the hill’s summit, but then had to wait by the moat of the fortress until scaling ladders had been brought up. Even so, by 09.30 the Americans had fought their way into the fortress. Meanwhile the other two columns has bypassed the fortress and advanced under heavy fire along the causeways leading to the Belen and San Cosme gates ofÎ Mexico City. By nightfall the Americans had taken both gates but, as the day’s losses had been 116 killed and 665 wounded, the following day’s fighting in Mexico City proper was the subject of unhappy anticipation for the American soldiers. The Mexicans had suffered about 1,800 casualties in the Chapultepec fighting alone, but the overall losses for the day were obviously far higher.
Threat of urban fighting lifted
On 14 September there loomed the threat of bloody house-to-house fighting, and throughout the night the Americans prepared for the ordeal. During the night Santa Anna’s men pulled back, however, and at dawn the remaining Mexicans surrendered just as the Americans were about to start the barrage they had planned as a preface to the assault on Mexico City proper. Scott’s army immediately occupied the city.
On the same day the American garrison of Puebla was taken under siege, but held out until 14 October 14, when a relief force arrived from Vera Cruz and drove off the Mexican besiegers.
For two months the only government in Mexico was the American military administration, and it was only in November that the Mexicans organised a government that could undertake meaningful peace negotiations. At this point Trist was ordered back to the USA and Scott ordered to resume the war. Trist and Scott chose to assume that President Polk’s administration did not understand the situation and continued negotiations. Finally the military commander was ordered home to face politically inspired charges that were later withdrawn.
The Treaty of Guadalupe Hidalgo was signed on 2 February 1848. The treaty confirmed the southern frontier of Texas, ceded to the USA the areas now comprising all of California, Nevada and Utah, most of Arizona and New Mexico, and portions of Colorado and Wyoming. In return for these huge territories the USA paid Mexico $15 million and agreed to assume responsibility for all unpaid claims against Mexico by American nationals. The treaty was ratified by the US Senate on 10 March, but because of growing political opposition in Mexico it was 30 May before the two countries’ ratifications were exchanged.
On 12 June the last American forces in Mexico City were withdrawn, and the last US soldiers in Mexico boarded their transports in Vera Cruz during 1 August.