Crow Agency is a census-designated place (CDP) in Big Horn County, Montana, United States and is near the actual location for the Little Bighorn National Monument and re-enactment produced by the Real Bird family known as Battle of the Little Bighorn Reenactment. The population was 1,616 at the 2010 census. It is the governmental headquarters of the Crow Native Americans. It is also the location of the "agency offices" where the federal Superintendent of the Crow Indian Reservation and his staff interacts with the Crow Tribe, pursuant to federal treaties and statutes.

Big Horn County is a county located in the U.S. state of Montana. As of the 2020 census, the population was 13,124. The county seat is Hardin. The county, like the river and the mountain range, is named after the bighorn sheep in the Rocky Mountains. The county was founded in 1913. It is located on the south line of the state.