Welcome to the Custer State Park. One of the largest national parks in the United States of America. And home to thousands of Bison, the largest animals in North America. Custer National park was named after George Armstrong Custer, who led an expedition that discovered gold there in 1874. It became a protected area in 1913 and a state park in 1919. Custer State park is home to one of the largest herds of Bison in the world. With over 1500 individuals roaming here alone.