The first catalogue of the Library of Congress was a ten-page pamphlet issued in April 1802: Catalogue of Books, Maps, and Charts, Belonging to the Library of the Two Houses of Congress. This listed the original collection according to size: folios, quartos, octavos, and duodecimos, with estimated values for each, followed by nine maps and charts.
In October 1803 the first supplement appeared: Supplemental Catalogue of Books, Maps, Charts, Belonging to the Library of the Two Houses of Congress. This 7-page pamphlet listed 180 volumes added since April 1802.
Sabin 15560 & 15561.