 It is owned by MGM Growth Properties and operated by MGM Resorts International.Originally constructed in 1934, Northfield Park racetrack was originally known as Sportsman Park, with a focus on midget car racing.After 20 years as a successful car racing facility, interest began to wane and in 1956, Sportsman Park was demolished to make way for what would eventually become one of the nation's premier harness racing tracks under the leadership of Carl Milstein, a well known real estate developer and businessman.