the 1926 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 from august 16 until august 23 while the men's tournament ran from 13 september until 18 september. it was the 46th staging of the u.s. national championships and the fourth grand slam tennis event of the year.