How large was the U.S. Army at the outbreak of the Mexican-American War?

At the outbreak of the Mexican-American War in 1846, the authorized strength of the United States Army was 8,613 troops.1

Following the conclusion of the Second Seminole War in 1842, the army had been reduced to this level, with its personnel scattered across more than 100 posts throughout the country. During the course of the Mexican-American War, the regular army was subsequently increased to more than 30,000 troops, supplemented by approximately 60,000 recruited volunteers.12