The Old Petaluma Opera House (also known as the Maclay Building) was built in 1870 as a theater, lecture hall, and dance hall. In 1901, the upper floors were converted to office and meeting space, the street level was remodeled for retail space, and a new prefabricated cast iron facade was installed. The property was listed on the National Register of Historic Places in 1978.
In recent memory, the space has been a series of drinking and dining establishments. It was Finbar Devine’s from 2003 to 2008, then McGuire’s Irish Pub from 2008 to 2021.
After McGuire’s closed in 2021, a victim of the COVID-19 shutdowns, a new owner purchased the property and in 2022 announced a plan to reopen the business as The Kentucky. In April 2025, it was revealed that The Kentucky would be a piano bar, set to open later that year. However, to date, the building remains shuttered, and the unveiling of The Kentucky remains on hold.