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.
| 1966 U.S. National Championships | |
|---|---|
| Date | September 1–11 |
| Edition | 86th |
| Category | Grand Slam (ITF) |
| Surface | Grass |
| Location | Forest Hills, Queens New York City, United States |
| Venue | West Side Tennis Club |
| Champions | |
| Men's singles | |
 Fred Stolle[1] | |
| Women's singles | |
 Maria Bueno | |
| Men's doubles | |
| Roy Emerson / Fred Stolle | |
| Women's doubles | |
Maria Bueno /  Nancy Richey | |
| Mixed doubles | |
| Donna Floyd / Owen Davidson | |
Finals
Men's singles
Fred Stolle defeated John Newcombe 4–6, 12–10, 6–3, 6–4
Women's singles
Maria Bueno defeated Nancy Richey 6–3, 6–1
Men's doubles
Roy Emerson / Fred Stolle defeated Clark Graebner / Dennis Ralston 6–4, 6–4, 6–4 [2]
Women's doubles
Maria Bueno / Nancy Richey defeated Rosie Casals / Billie Jean King 6–3, 6–4 [3]
Mixed doubles
Donna Floyd-Fales / Owen Davidson defeated Carol Hanks Aucamp / Ed Rubinoff 6–1, 6–3 [4]