This Day in Military History

May 13, 1846: At the request of President James Polk (on May 11), Congress declared war against Mexico. The Mexican-American War would end in 1848, with the United States gaining 525,000 square miles of land, including what is now Texas, California, Nevada, Utah, New Mexico, Arizona, and parts of Colorado and Wyoming.

Quote of the Day: “In further vindication of our rights and defense of our territory, I invoke the prompt action of Congress to recognize the existence of the war, and to place at the disposition of the Executive the means of prosecuting the war with vigor, and thus hastening the restoration of peace.” – President James K. Polk

Brandus, Paul. This Day in U.S. Military History (p. 124). Bernan Press. Kindle Edition.