The tiny two room jail was built in 1911 by John Higgins on property purchased from the estate of Thomas Johnston. The barn behind the jail was constructed by Johnston in 1877. The facility served as a sheriff's sub-station with an office and two small cells until the mid-1960s. The cells were used essentially as overnight holding cells for any prisoners awaiting transfer to the Redwood City jail and as a place to sleep off a binge by local citizens. In 1986 the County of San Mateo gave the building to the City of Half Moon Bay. Under the city's sponsorship, the Spanishtown Historical Society restored the jail to serve as a historical museum in 1990.
Other points of historical interest in and around Half Moon Bay can be found at Half Moon Bay Coastside Chamber of Commerce: Coastside History.
When this cache was placed, the groundskeeper was aware of it and thought it was a great idea to draw more visitors to the jail.