Napa Valley Museum boasts an intriguing collection, of objects and artifacts rooted in Napa's pioneering and wine making history. The museum is housed in fashionably reconstructed quarters of what was once the California State Veterans Home. Three galleries are housed within the museum, each dedicated to a different aspect of local history. The exhibit spaces are intelligently arranged and well lit, making good use of Napa's abundant natural light. Its educational programs are great, particularly strong hands-on art training for kids.

The Petaluma Wildlife & Natural Science Museum has a huge collection of taxidermied animals as well as live animals, and is open to the public every Saturday. The property also includes an aviary, dioramas, and a fossil and mineral collection.

Robert Louis Stevenson Museum hosts an exhibit of Robert Louis Stevenson ephemera such as 8000 manuscripts, photos, letters and the like. It is, in fact, one of the largest collections of Robert Louis Stevenson's works outside of Scotland and a must-see for fans of his work. Virtually all of his first editions are here. Stevenson spent his honeymoon in the area and wrote The Silverado Squatters.