Jefferson Valley-Yorktown, commonly known as Jefferson Valley, is a census-designated place (CDP) located in the town of Yorktown in Westchester County, New York, United States.

[3] It is a hot spot for local shoppers, due to its Jefferson Valley Mall.

There were 5,526 housing units at an average density of 799.4 per square mile (308.7/km2).

The racial makeup of the CDP was 92.31% White, 2.33% African American, 0.11% Native American, 3.22% Asian, 0.01% Pacific Islander, 1.06% from other races, and 0.96% from two or more races.

Yorktown Central School District includes the southern portion of the Jefferson Valley-Yorktown census-designated place, while Lakeland Central School District has the northern portion.