Stephen Watts Kearny (August 30, 1794 - October 31, 1848) was a United States Army officer, noted for action during the Mexican American War.
Kearny was born in Newark, New Jersey and began studies at Columbia College in 1811, leaving school at the outbreak of the War of 1812 to join the Army. During the war he was cited for bravery and promoted to captain; afterward he continued a lifelong military career.
Immediately following the war he was assigned to the western frontier under the command of Gen. Henry Atkinson, and was involved in various military actions against Native Americans and the establishment of several frontier posts. Kearny was put in command of the Army of the West in May of 1846, and was soon afterward promoted to the rank of brigadier general.
At the outset of the Mexican American War, Kearny proceeded to Santa Fe, New Mexico at the head of a force of 1,700, taking control of the area and becoming its military governor on August 18, 1846. He ensured that a civilian government was in place there by the end of one month.
With his mission in Santa Fe complete, Kearny set out for California on September 25 with a much smaller unit (about 100 men). This group, after having suffered significant attrition during the march, were fought to a standstill at the Battle of San Pasqual.
The surviving force was able to unite with naval reinforcements who had landed in San Diego, under the command of Commodore Robert F. Stockton. This combined force consolidated control of San Diego in December, and in January of 1847 also took San Gabriel and Los Angeles.
Kearny, as ranking Army officer, asserted the right to be in command of the area at the end of hostilities, beginning a rivalry with Stockton. When Mexican forces in the area capitulated on January 13, however, they did so to neither Stockton nor Kearny, but rather to Lt. Col. John C. Frémont. Stockton seized upon this and appointed Frémont military governor of the area. Kearny appealed to Washington, and upon receiving confirmation of his authority took command, having Frémont relieved and arrested (he was later convicted at court-martial).
Kearny remained military governor of California through August, at which point he returned east to Fort Leavenworth, Kansas and later proceeded to Mexico, where he was appointed governor of Veracruz and later of Mexico City. He was promoted to major general In September 1848, over the heated opposition of Senator Thomas Hart Benton (Frémont's father-in-law), but died in St. Louis, Missouri the following month as a result of a tropical disease he had contracted while in Veracruz.
Kearny is the namesake (via misspelling) of Kearney, Nebraska.