John Langdon (fl. c. 1790 - 1840) was an auctioneer, bookseller, and part time publisher active in New York during the mid 19th Century. Langdon's publishing ventures seem to have been minimal and associated exclusively with his regular auction offering. Several of his auction catalogues survive including one dated to 1798. Langdon's sole map publication is an rarely seen pocket map of New York City that appears to be either a reissue or an outright theft S. Mark's map of 1827. A John Langdon is known to have been president of the Senate during the investiture of George Washington as President, but it is unclear if it is the same person. Langdon had his offices at 151 Fulton Street, New York City.