The Old Stone Fort Museum stands on the Stephen F. Austin State University campus, built in 1936 with stones from the earlier Spanish trading post and fort associated with Nacogdoches. The building is a reconstruction, but the story it tells is central to the city.
Inside, exhibits cover Spanish, Mexican, and Republic of Texas East Texas. It is a good first stop if you want the town's many flags and shifting loyalties to make sense before wandering downtown.