FAQ for
Night at the Museum (2006) More at IMDb Pro »

U.S.V. stands for United States Volunteers. Specifically, Teddy Roosevelt was assigned to the 1st United States Volunteer Cavalry (one of 3 Volunteer Cavalry regiments raised for the Spanish-American War) which was nicknamed as "The Rough Riders" by the American press. The 1st United States Volunteer Cavalry was the only regiment to see any action during 1898 in the Spanish-American War. When Colonel Leonard Wood became commander of the cavalry brigade (consisting of 1st U.S. Cavalry, 10th U.S. Cavalry, and 1st U.S.V. Cavalry), "The Rough Riders" was renamed as "Roosevelt's Rough Riders."