Currently servving as a Historical Museum, the cornerstone for this stately Carnegie Library was laid in 1904. The building, designed by local architect Brainerd Jones and built from locally quarried stone, features the largest free-standing leaded glass dome in Northern California. The building is in the neo-classical style, featuring original fan-glass windows, round leaded-glass windows, also original interior wood paneling and columns. With outstanding acoustic qualities, it is often referred to as 'Petaluma's Carnegie Hall'.