the 1925 u.s. national championships (now known as the us open) was a tennis tournament that took place on the outdoor grass courts at the west side tennis club, forest hills in new york, united states. the women's tournament was held form 17 august until 24 august while the men's tournament ran from 14 september until 19 september. it was the 45th staging of the u.s. national championships and the fourth grand slam tennis event of the year.