1881 U.S. National Championships – Singles

Richard Sears defeated William Glyn in the final 6–0 6–3 6–2 to win the inaugural men's singles tennis title at the 1881 U.S. National Championships. Each match was the best of three sets, except for the final which was best of five. Winner of a set was the player who won six games first; no two-game advantage was required. Participation was restricted to USNLTA club members.