The 1919 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 City, United States. The women's tournament was held from June 16 until June 20 while the men's tournament ran from August 26 until September 4. This event marked the 39th staging of the U.S. National Championships and was the second Grand Slam tennis event of the year.

Champions

Men's singles

🇺🇸 Bill Johnston defeated 🇺🇸 Bill Tilden 6–4, 6–4, 6–3

Women's singles

🇺🇸 Hazel Hotchkiss Wightman defeated 🇺🇸 Marion Zinderstein 6–1, 6–2

Men's doubles

🇦🇺 Norman Brookes / 🇦🇺 Gerald Patterson defeated 🇺🇸 Bill Tilden / 🇺🇸 Vincent Richards 8–6, 6–3, 4–6, 4–6, 6–2

Women's doubles

🇺🇸 Marion Zinderstein / 🇺🇸 Eleanor Goss defeated 🇺🇸 Eleonora Sears / 🇺🇸 Hazel Wightman 10–8, 9–7

Mixed doubles

🇺🇸 Marion Zinderstein / 🇺🇸 Vincent Richards defeated 🇺🇸 Florence Ballin / 🇺🇸 Bill Tilden 2–6, 11–9, 6–2