 He was promoted to first lieutenant on March 2, 1853.In 1854, Lieutenant Benson was posted in Florida (likely since 1849) during the Army's mission to survey the state and build roads, protect settlers, and relocate the indigenous Seminole tribe—all of which contributed to the Third Seminole War (1855-58).He was heavily involved in the Army's surveying efforts, actively scouting road paths in the field, alternately present at Fort Myers, Fort Meade, Fort Thompson, and Fort Center.