US National Archives
Nara: Teaching With Documents: Black Soldiers in the Civil War
This comprehensive site from the National Archives and Records Administration (NARA) describes the history of the participation of colored troops in the Civil War and government efforts to research and compile records about them....
US National Archives
Our Documents: War Dept General Order 143: Creation of Us Colored Troops (1863)
Original document that permitted the recruitment of black troops during the Civil War. Read about events and issues leading up to and following the 1863 establishment of the Bureau of Colored Troops.
Other
Hart Island History: Ny State's Civil War "u.s. Colored Troops"
After a brief history of African-American regiments from New York, you can read about the United Stated Colored Troops in general, where they fought, how they were paid, and the number of casualties among the troops.
Other
Maryland Department of Natural Resources: Point Lookout State Park History
A brief description of the prisoner-of-war camp at Point Lookout, Maryland.