Seamen's Protection Certificates were authorized by Congress in 1796 to identify American merchant seamen as citizens of the United States and, as such, entitled to protection against impressment at sea. This work is an index to the names of merchant seamen who made application for a Seamen's Protection Certificate (SPC) at the Port of Philadelphia between 1796 and 1823. The names of 14, 397 seamen appear in this new volume, and each is identified according to the date of the SPC application, age, race, and state or country of birth.