The Wiltshire Museum on Long Street is modest in size but extraordinary in content. Its Bronze Age gallery holds the Bush Barrow gold — a lozenge, a belt hook, and other objects that belonged to a man buried near Stonehenge around 1900 BC and thought to have been a chieftain of some importance. These objects are among the finest prehistoric metalwork in Britain, and unlike the Stonehenge visitor centre, the museum lets you get close.
Beyond the Bush Barrow material, the museum has strong collections on Avebury, the Wiltshire chalk figures, and the broader prehistoric landscape. The archaeology displays are well written and accessible without being dumbed down. There is also a natural history section and a local history gallery tracing Devizes from its Norman foundation to the present. Allow two hours minimum. The museum shop is good for serious books on Wiltshire prehistory.