Petaluma Historical Museum/Library, 20 4th St., houses permanent and rotating exhibits. Philanthropist Andrew Carnegie awarded the town $12,500 toward the building's construction in 1903. An architectural highlight is the free-standing stained-glass dome.
Upstairs a permanent exhibit recounts local history, with artifacts and photographs pertaining to early river commerce with San Francisco, the city's famed "Egg Capital of the World" years, the poultry industry and notable 19th-century buildings. Classical concerts also are offered.