Hi-
One of my brickwalls claimed to have been discharged in the 1870s, does anyone know where I could find that info if it exists? He claimed to have been in the Civil War, then at Leavenworth, but I can't find any real evidence. no pension exists for him, nothing in the ancestry.com civil war info on the Civil War soldiers.
The most likely place would be to check with the National Archives for post Civil War records. This may fall into what was called the Indian War records. Depending on the time in the 1870's. Leavenworth was a prison during that time. Even if he was dishonorably discharged should have some record of his service.