Copies of 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 C2842 for all transactions in each block for specified periods of time. The maps were maintained in the land records division of the clerk's office. The copies sent to the Archives include contact negatives and mounted prints. Most of them are poor quality and contain many unattributed annotations. The documents are being included in the plats project because the court did use them for reference purposes. Better copies do exist in (Block Maps) in series C2845. Good copies of the maps, but including only the blocks originally set up in 1886, are found also in Special Collections in series SC1427-25.