With the United States national average horse racing purse of $20,762 in 2005, the average 2005 purse for DelPark of $30,650 has helped to attract more talented contenders and more first-time competitors to the venue for the 20 racing seasons. Race purses have increased in recent years owing to increasing casino revenues. The facility opened on June 26, 1937, and today is the only thoroughbred horse racing track in the state of Delaware. Harris of Media, PA., was hired as the architectural engineer. a designer of twenty-three racing courses, designed and built Delaware Park Racetrack in partnership with Donald P. Thoroughbred racing Aerial view of Delaware Park Racetrack A race begins on a rainy fall day at Delaware Park. It is located just outside the city of Wilmington, and about 30 miles from Philadelphia. Delaware Park (also known as DelPark) is an American Thoroughbred horse racing track, casino, and golf course in Stanton, Delaware.