The Archaeological Museum near the fort entrance houses finds from the Chitradurga region: coins, inscriptions, weapons, and ceramics that trace occupation of the area from prehistoric times through the medieval period. There are pieces from the early Buddhist and Jain periods as well as material from the fort itself — cannon balls, structural fragments, and objects recovered during conservation work.
The museum is not large but it gives useful context for what you're about to walk through in the fort. Hire a guide at the entrance if you want the stories explained — the exhibits are not labelled in depth.