The Nassau County Stakes is an American Thoroughbred horse race run annually at Belmont Park in Elmont, Nassau County, New York. A Grade III event, it is open to three-year-old fillies willing to run the distance of seven furlongs on dirt. The race offers a purse $200,000 added. Inaugurated in 1996, it is named after the county on Long Island in which Belmont Park is located. On November 28, 2007, this Grade II stakes race was downgraded to a Grade III by the American Graded Stakes Committee.