Texas declared its independence from Mexico in 1836. The United States quickly recognized the Republic of Texas, but did not admit Texas as a state, due to controversy over slavery expansion. By 1844, though, annexation negotiations began, despite fear of war with Mexico over the issue. Texas was formally admitted to the Union in December 1845. Skirmishes began in the spring of 1846 between General Zachary Taylor's troops, stationed on a disputed strip of land between the Rio Grande and the Nueces rivers, and Mexican troops gathering at the border, intending to invade Texas. In April 1846, the Mexican government declared war; the United States Congress passed a war resolution on May 11, 1846, authorizing the president to call up 50,000 troops and appropriating $10 million for the war effort.

General E.P. Gaines, the officer in charge at New Orleans, feared an imminent Mexican invasion and requested troops from western states. Missouri sent 650 volunteers, but since Gaines was not authorized to raise the troops, his order was overruled and the men sent home. This regiment was known as the "St. Louis Legion." Governor John C. Edwards officially called for volunteers in May 1846; over 1,350 Missourians answered. Eight mounted companies were formed, each consisting of 856 men. Jackson, Lafayette, Clay, Saline, Franklin, Cole, Howard, and Callaway counties each fostered one company, known respectively as Companies A through H.

Men from Cole and Platte counties made up a battalion of infantry numbering 145 men; St. Louis provided a battalion of light artillery of two companies (250 men). These troops, and the First Dragoons of the U.S. Army, made up the Army of the West, serving under General Stephen W. Kearny. Colonel Alexander Doniphan was selected as second in command. After Kearny turned west toward California, Doniphan led the troops to play a major role in several victories in northern Mexico.

Missouri also furnished other troops, including the Second Missouri Mounted Volunteers and a separate battalion of mounted troops. They arrived in Mexico in September 1846 and were followed in July 1847 by the Third Regiment of Missouri Mounted Volunteers.

Source: Soldiers Database: War of 1812 - World War I

Source: Ray County Chapters, Articles from the "Richmond Missourian", volume 2 -1931, p 84-85.