The marker that has a black plaque on it marks the place where Custer died.
George Armstrong Custer (December 5, 1839 – June 25, 1876) was a United States Army officer and cavalry commander in the American Civil War and the Indian Wars. Raised in Michigan and Ohio, Custer was admitted to West Point in 1858, where he graduated last in his class. However, with the outbreak of the Civil War, all potential officers were needed, and Custer was called to serve with the Union Army.