Electronic index to certificates of survey and patents, created from a card index, for land now in Delaware, Pennsylvania, and District of Columbia. Entries give name, tract name, current jurisdiction, patent date, acreage, and citation(s). One set of cards includes Delaware and Pennsylvania and the other District of Columbia. Within each group entries are arranged alphabetically by tract name. The index includes 1013 entries and provides references to Land Office (Patent Record) in series S11. The patent records do not contain plats. The original index cards are available to view in the Archives Searchroom under Index 55.