Maps of Baltimore City showing block numbers that are used for organizing references to land transactions recorded by the Superior Court, 1851-1982, and after that the Circuit Court. The maps show the block numbers originally assigned in 1886 and the additional ones after the annexations of 1888 and 1918. Block numbers remain the same regardless of changes in street names or house numbers. The block book maps represent the first step in searching for land records in Baltimore City. They provide the block number for specific addresses. Researchers then use (Block Book) in series C2838 and C2839 and (Block Book, New Annex) in series C2840 to obtain references to (Land Records) in series C205 and C2482 for all transactions in each block for specified periods of time. The maps were maintained by the City Department of Public Works and comprise the most complete and best preserved set of records. For those from the court clerk's office, see (Block Maps) in series C2837.