William duPont, Jr. a designer of twenty-three racing courses, designed and built Delaware Park Racetrack in partnership with Donald P. Ross. Phillip T. Harris of Media, PA., was hired as the architectural engineer. The facility opened on June 26, 1937 and today is the only thoroughbred horse racing track in the state of Delaware. Races are run from May to October.
Race purses have increased in recent years owing to increasing casino revenues. 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 2005 and 2006 racing seasons. The 2005 average purse for DelPark placed Delaware fifth among states of the United States; the first rank for average purse was held by New York at $41,229 per race.
Delaware Park entries are drawn well in advance which often results in short fields after several late scratches. It is not uncommon to see four- or even three-horse fields at Delaware in bad weather. Small fields are an issue because Parx Racing (formerly Philadelphia Park Racetrack), Laurel Park Racecourse, Pimlico Race Course, Charles Town, Mountaineer, and Colonial Downs all run simultaneously. Delaware Park is not part of a racing circuit, but is instead a standalone track. During the off-season, horses who do not lay over for the spring meet often disperse to the above mid-Atlantic tracks, plus New York, while others go to Florida. Conversely, many Florida-based horses "summer" at Delaware.
Delaware Park also offers simulcasts of races from other tracks. Wagering on live and simulcast horse races is offered at the Sports Book at Delaware Park.