The original Old Stone Mill of James Alexander Forbes, was built in 1850, the first permanent commercial building constructed in Los Gatos. In 1880, an addition was built next to the four story mill to store flour and supplies. The Forbes Mill Annex, which today is the only part of the mill still standing, is now the home of the Los Gatos History Museum.
The above postcard shows the mill with the annex under construction. The photo below is the annex today as the History Museum.