Bay Area History

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Bay Area History is a website that provides access to historical maps and other historical resources for the San Francisco Bay Area.

Want more resources? Check out these websites:

• OpenSFHistory
• San Francisco Historical Photograph Collection - 6th Floor

San Francisco - Historical Block Maps

San Francisco block maps, officially called "Assessor's Block Books," are detailed maps that divide the city into numbered blocks and lots. They show property lines, lot dimensions, and Assessor's Parcel Numbers (APNs), which are used for property tax assessment. Essentially, they are the official record of parcel boundaries within San Francisco.

Bay Area History has block maps available from 1906 to 2021. Year availability varies by block. To find a block number, use a tool like the San Francisco Property Information Map (PIM)