Mexican American War Timeline





The New Republic of Mexico grants lands in the sparely populated Texas state on the condition settlers convert to Catholicism and assume Mexican citizenship. The Mexicans hoped this  to help control raids by Commanches and stop possible expansion into the area by the United States by integrating these new settlers into Mexican society.


                                                                       Mexican land grant


Many Americans come to settle in Texas. By 1835  there were 30,000 Americans and only around 8,000 Mexicans .Mexico orders halt to American immigration, but Americans continue to cross the border to settle.


President Santa Anna abolishes the federal constitution of Mexico, replaces it with a new centralist constitution. The militias of Mexican states ordered to be disbanded. Many states, including Texas revolt, fearing they would live under a tyrant with no representation.


Oct 2 Texians revolt against Mexico.



March 6 Fall of the Alamo


April 26 Battle of San Jacinto Santa Anna captured and forced to sign the Treaties of Velasco, which he agreed to withdraw his troops from Texan soil and recognizes Texas independence .Mexican government deposed him in absentia and disavows his treaty. Mexico still regards Texas as part of Mexico,but is too weak by internal disturbances to try to regain it.



                                                                                           Pastry War

Santa Anna becomes a hero fighting the French ( 1838 Pastry War) and losing part of his leg to shellfire and re-elected president.


Dec 6 in Mexico City troops rise against Santa Anna, who is overthrown. The mutineers select Gen. Jose de Joaquin de Herrera as president.

June 3 Santa Anna exiled to Cuba, where he plots his return as his hero Napoleon did from Elba island.










































U.S. President John Tyler, who has become president after the death of president Harrison (who died  on April 4, 1841 from a cold, a month after delivering a two hour inaugural speech on a cold and rainy day) wishes to annex Texas to gain prestige for a new political party he wished to found. The Senate rejects an annexation treaty due to anti-slavery forces,such as former President Martin Van Buren, who were afraid Texas would become a slave holding state.



                                                    Republic of Texan $10


Feb 28  Congress annexes Texas in a joint resolution. The Texan claim to the Rio Grande boundary had been omitted from the annexation resolution to help secure passage after the annexation treaty failed in the Senate.


March 1 United States Congress votes to annex the Republic of Texas


                                                                Pres. Polk

March 4 Expansionist James K. Polk (49) becomes president of the US. One of the goals of his administration is acquire California and New Mexico from Mexico. The main interest was San Francisco Bay as an access point for trade with Asia.Polk claims the Rio Grande as the boundary between the U.S. and Mexico .Americans base claims on the   Treaties of Velasco. Mexico, however, had never ratified these treaties, which were signed by Santa Anna while he was a prisoner in Texas. The disputed area had never been a part of the viceroy of Texas under Mexican rule, but had been parts of Tamaulipas, Coahuila, Chihuahua and Nuevo Mexico .



                                                                   Pres Herrera

March 28 Mexican Senate  breaks off negotiations, gives interim President Herrera. authority to raise troops and prepare for war. Herrera preferred peaceful negotiations.


March 6 Mexican ambassador in Washing requests passport-Mexico regards Texas as a breakaway province


July 4 Anglo-Americans in Texas accept U.S. terms for annexation



                                                                     Gen. Taylor

July 22-23 Polk orders Gen. Zachary Taylor to depart Fort Jessup, Louisiana into Texas with 1,500 troops. on the transport Alabama.


July 31 Taylor camps with army at Corpus Christi near the mouth of the Nueces River, regarded by Mexico as the Mexican-Texas border. By late Oct 3,500 regulars have gathered.


Nov 29 Former U.S. Congressmen John Slidell arrives at Veracruz to try to negotiate with the Mexican government'. He is authorized to offer $25 million  for the disputed Rio Grande border area  in Texas and Mexico's provinces of Alta California and Santa Fe de Nuevo Mexico. Mexicans considered this an insult to national honor.. When Mexican President JoseJoaquin de Herrera considers receiving Slidell in order to peacefully negotiate the problem of Texas annexation,he was accused of treason and deposed by followers of Santa Anna, but regains power.


Sept 15 Interim president  Herrera wins election and becomes president.


Dec2 - Polk reinstates the Monroe Doctrine and calls for western expansion




Dec 14 Herrera, assembles a force of 6,000 men. This was put under the command of General Mariano Paredes y Arrillaga and ordered north to fight the Americans. Paredes got as far as San Luis Potosíi but instead of marching north against the invaders, in December he turned back to the capital and overthrew President Herrera.


Dec 29 Texas becomes the 28th state of the United States  Mexico breaks diplomatic relations with the United States




















































































                                       Flag of the Yucatan Republic ( 1841-1848)

Jan 1 Yucatan declareds its independence from Mexico and its neutrality in the war with the United States


Jan 2 General Mariano Paredes y Arrillaga enters Mexico City, declared President of Mexico.


Feb 10 –Mormons begin their migration west from to the Great Salt Lake,


March 5 Federally commissioned explorer John C. Fremont approaches Monterey with a 60 man survey team, is ordered to leave California by Mexican authorities after stir up patriotic enthusiasm among the American settlers there. Fremont entrenches on Gavilan  (Mount Fremont) and is surrounded by a 350 man force under Gen.Jose Maria Castro. Fremont retreats after four days under cover of darkness.


March 8 Gen. Taylor is authorized to move south into disputed territory.


March 28 Gen. Taylor reaches the Rio Grande. The Mexican commander in Matamoros,Col. Francisco Mejia, considers this an invasion of Mexican territory, but is not authorized to attack. Taylor erects a camp named Fort Texas with 2,200 men. Mejia has 3,000 men under his command.


April 2 Gen. Mariano Arista appointed in command of the Army of the North to confront the Americans


April 11 Gen.  Arista reaches Matamoros, Taylor ordered to return to Corpus Christi within 24 hours. Taylor refuses.


April 25 a 1,600-strong Mexican cavalry detachment under Gen.Torrejon attacked a 70-man U.S. patrol that had been sent into the contested territory north of the Rio Grande at Carricitos. The Mexican cavalry routed the patrol, killing 16 U.S. soldiers in what later became known as the Thornton Affair after Captain Thornton who was in command.


May 3 Mexican artillery opens heavy fire against Fort Texas. Maj. Jacob Brown killed by shellfire, Fort Texas renames Fort Brown in his honor, which later becomes Brownsville.



May 7 Battle of Palo Alto. Gen.Arista with 3,300 confronts Taylor's 2,300. American 'flying artillery' wreak havok on Mexican lines. Mexican cavalry charge under Torrejon who are disperesed by accurate fire. Mexicans withdrawl by evening with 400 casualities, Americans have 9 killed.


May 8 Resaca de la Palma  Gen.Arista deploys his forces in an empty lake bed with his army in a narrow line. Taylor attacks his center, overrunning the Mexican artillery. Mexicans retreat across the Rio Grande. Mexican losses 200 killed, 39 Americans killed.


May 13 U.S. Congress declares war on Mexico 173-14 in the House, 40-2 in the Senate after learning of the Carricitos. incident.


May 17 Taylor crosses Rio Grande and takes Matamoros, which has been abandoned by the Mexican army. Arista retreats toward Linares, Nuevo Leon,losing many men in the desert. Arista resigns command to Gen.Jose Maria Ortega.


May 19 blockade of Tampico starts


May 20 Blockade of Veracruz starts. Revolts against Parede in Guadalajara.


June 12 America reaches compromise with Britain over Pacific Northwest with the Canadian-U.S. border set at the 49th parallel. 6,000 man Mexican government army arrives to besiege Guadalajara



July 4 American settlers in California declare themselves independent of Mexico and establish 'Bear Flag" Republic.


July 7 Mexican Congress declares war on the U.S.


Aug 5 Gen.Jose Mariano Salas deposes Paredes as president.



Aug 16 Santa Anna returns to Veracruz after exile in Cuba on a British ship.Washington believes he will help conclude a peace.


Aug18 Gen.Kearny occupies Santa Fe without a fight.


Aug 19 Taylor marches toward Mier and Camargo with 3,200 regulars and 3,000 volunteers, leaving 4,700 for garrison duty.


Sept 15 Santa Anna enters Mexico City to great reception


Sept 19 Taylor arrives at Monterrey with 6,645 troops,which is defended by a formidable citadel,called the Black Fort by the Americans. the Mexican commander  Ampudia has 7,000 Mexican regulars and 2-3,000 militia.



Sept 24 Most of Monterrey in American hands after fierce house to house fighting, Ampudia asks for terms. Mexican army allowed to march out with arms. Americans suffer 120 killed, Mexicans 700 casualties.


Sept 23 Californio guerrillas under Servulo Verda attack a 48 man American garrison in Loa Angles, forcing them to surrender.


Sept 28 Santa Anna departs Mexico City to San Luis Potosi, gathering a 21,500 man army in four months.


Nov 13 Taylor occupies undefended Saltillo


Nov 30 The U.S. decides to transport another army to Veracruz to attack Mexico City, to be led by Gen. Winfield Scott.


Dec 2 Santa Anna inaugurated as president


Dec 25 El Paso taken by Doniphan, Mexican lose 100 in cavalry charge, no Americans killed.


Dec 26 Taylor arrives at Brazos de Santiago (near BrownsvilleTexas)


Dec 28 Stockton and Kearny with 600 men attack Flores with 450 men and retake Los Angles, the last Mexican stronghold in California.





































































Jan 13 Lt.Richey, who is carrying Scott's campaign plans to Gen.Taylor is killed trying to buy provisions in Villagran, the plans are forwarded to Santa Anna at San Luis Potosi.The Treaty of Cahuenga ends the fighting in the Mexican-American War in California


Jan 28 Santa Anna decides to attack Taylor after learning of his deminished strength from the captured plans. The vanguard is the San Patrico Company of Irish-American deserters of a 20,000 man Mexican army. Only 14,000 survive the grueling desert march to Encarnacion. Santa Anna prepares to attack Taylor's positron at Coahuila.


Jan 30 – Yerba Buena, California is renamed San Francisco.


Feb 20 a 400 American recon unit spots 4,000 Mexican cavalry in advance of Santa Anna's army at Hediona Ranch and ride back to warn Taylor. Taylor decides to fall back with his 4,800 troops to Buena Vista Hacienda, an easier to defend narrow pass.



Feb 22 Battle of Buena Vista  Shortly after sunrise, Santa Anna's 18,000 appear and sends a surrender order to Taylor, who rejects it ( 'Tell Santa Anna to go to hell !'). Indecisive firefights for high ground ensues.The flying artillery breaks up Mexican attacks. Mexicans lose 1,800, Americans lose 267 killed with 1,500 desertions.Santa Anna orders a retreat at night toward Agua Nueva. Taylor retires toward Monterrey.


Feb 28 Battle of Sacramento. American force entering Mexico from El Paso of 924 under Doniphan attacks 2,400 Mexican force of the Sacramento River north of Chihuahua City. Mexicans lose 300 killed, most in a 800 man cavalry charge. America lose one killed and occupy Chihuahua City.


March 9 American landing at Veracruz.8,600 soldiers land by nightfall.. Siege of Veracruz begins.


March 21 10,500 return with Santa Anna to San Luis Potosi.


March 28 Veracruz surrenders


April 14 Battle of Cerro Gordo Santa Anna deploys 12,000 raw troops and 43 field pieces on the National Highway to Mexico City to block the American advance. A flanking maneuver and frontal assault breaks the Mexican line.Special Cavalry Division. Army Corps of Engineers Capt. Robert E. Lee discovered a mountain trail around Santa Anna's position Mexican troops retreat in panic, 3,000 Mexican prisoners taken.Americans lose 63 killed.General Santa Anna, caught off guard by the Fourth Regiment of the Illinois Volunteer Infantry, was compelled to ride off without his artificial leg, which was captured and is still displayed in Illinois.


April 20  American army enters deserted Jalapa.


April 21 Santa Anna arrives at Orizaba and begins to reassemble 4,000 of his defeated troops.


May 15 Scott's army enters Puebla with no opposition


May 28 Scott has lost 3,000 volunteer militia as the terms of their enlistment has expired.and is left with 5,820 - to few to attack Mexico City and wait for reinforcements.


June 14 Perry in a  squadron of steamers takes Villahermosa in Tobasco. Mexican guerillas surround American garrison there., forcing the American garrison to leave by July 19.


July 8 Scott is reinforced at Puebla by 4,500 troops.


Aug 7 Scott begins offensive against Mexico City. Scott now has 14,000 troops, 2,500 of which are sick.


Aug 10 Mexican fortify El Penon Hill with 7,000 troops and 30 cannons.


Aug 19 Americans have breakthrough at San Geronimo, a surprise attack kills 700 Mexicans, Mexicans flee across river at  Churubusco and Coyoacan. The San Mateo Convent  is taken with some of the San Patrico Battalion, 30 out of 69 are executed.


Aug 20 Santa Anna flees back to Mexico City, Mexican loses are 4,000 dead and 3,000 captured. Americans have lost 139 killed.


Aug 22 Scott grants Santa Anna a truce,hoping he will ask for terms.


Sept 7 Americans learn Mexicans have fortified a strong position at Molino del Rey. Scott sends 3,500 under Worth to take it, which falls after a fierce battle. Americans lose 116 killed.


Sept 12  Scott orders to bombardment of the hilltop castle of Chapultepec, the last major defense before Mexico City, defended by 260 defenders under Gen.Bravo, 50 of which are cadets. The next day the lower defenses are overcome in a fierce hand to hand struggle.Scaling ladders are brought up and by 9:30 AM Col. Joseph E. Johnsons troops have unfurled American flag atop the castle. Six cadets fight to the death, one jumping to his death holding the Mexican flag and are known as los Ninos Heros today.(Boy Heros). Santa Ana flees Mexico City.



Sept 14 Scott's army enters Mexico City main square by noon. A couple of days of severe rioting follows. Santa Anna regroups at Guadalupe.


Sept 15 Santa Anna resigns in favor of Chief Justice Manuel de le Pena y Pena.


Oct 8 Santa Anna ordered to turn over military command to Rincon and prepare to stand trial for his conduct of the war.


Nov 10 Mazatlan is taken after Mexican garrison withdraws.


Nov 11 elections held in unoccupied parts of Mexico. Anaya become interim president.





Jan 24 gold  discovered at Sutter's Mill, in Coloma, California


Feb 2 Treaty of Guadalupe Hidalgo signed. America takes California,Nevada,Utah,Colorado,Arizona and New Mexico, Mexico loses 55% of its pre war territory. (2/3 if Texas is included) America pays $15 million in compensation and assumes responsibility for $3,5 million in claims by U.S. citizens against Mexico.Mexicans living in lands ceded ( about 80,000) were to be treated as U.S. citizens.


July 31 last of 18,300 American troops depart Mexico




Santa Anna dies in obscurity in Mexico City. Buried at Tepeyac Cemetery, near Guadalupe Hidalgo



Last veteran of Mexican-American War,sailor Owen Edgar, dies