The museum occupies the old town jail on Praça Tiradentes — a long, low building completed in 1846 after the gold had run out and Ouro Preto could no longer afford grandeur. Two floors of galleries trace the colonial gold rush, the slave economy that powered it, and the 1789 Inconfidência conspiracy that the town is now identified with.
The collection includes Aleijadinho sketches and tools, period furniture, and colonial silverwork. Allow an hour and a half. Information panels are in Portuguese only — the gift shop sells a useful English guide.