The 1966 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 tournament ran from 1 September until 11 September. It was the 86th staging of the U.S. National Championships, and the fourth Grand Slam tennis event of 1966.
See main article: 1966 U.S. National Championships – Men's singles. 
Fred Stolle defeated John Newcombe 4–6, 12–10, 6–3, 6–4
See main article: 1966 U.S. National Championships – Women's singles. 
Maria Bueno defeated 
Nancy Richey 6–3, 6–1
Roy Emerson / Fred Stolle defeated Clark Graebner / Dennis Ralston 6–4, 6–4, 6–4 [1]
Maria Bueno / Nancy Richey defeated Rosie Casals / Billie Jean King 6–3, 6–4 [2]
Donna Floyd-Fales / Owen Davidson defeated Carol Hanks Aucamp / Ed Rubinoff 6–1, 6–3 [3]