The 1904 U.S. National Championships was a tennis tournament that took place in June and August of 1904. The women's tournament was held from June 21 to June 25 on the outdoor grass courts at the Philadelphia Cricket Club in Philadelphia, Pennsylvania. The men's tournament was held from August 21 to August 31 on the outdoor grass courts at the Newport Casino in Newport, Rhode Island. It was the 24th U.S. National Championships and the second Grand Slam tournament of the year.