A harness racetrack (also one of the few tracks built in the country dedicated solely for harness racing) was opened for simulcast wagering on March 17, 1999, while the first day of live racing was on April 19 on the same year, replacing Foxboro racetrack which was closed in 1997.

Two competing individuals who wanted to manage the track were Gary Piontkowski, who had managed Foxboro under Sarkis, and Lou Giuliano, who applied to purchase the land and construction of the track. He is a real estate developer who would lease the track to Piontkowski’s company for $1 million per year. The two had been in dispute, filing lawsuits against each other. However, none of them succeeded, and Giuliano failed to purchase the land, retaining the ownership to Piontkowski.

Plainridge was the State’s first gaming applicant, submitting its $400,000 application fee as soon as casino legislation was approved in 2011. The track began constructing a 1,000-car parking garage in late 2012, hoping to demonstrate to the Gaming Commission that its proposal would be the quickest to open and begin generating tax revenue. In early 2013, state investigators found that Piontkowski had taken over $1 million in cash from the track’s money room over the years. As a result, the owners pushed Piontkowski out as president and bought out his shares. The track’s new president vowed to change the organization’s “culture”, but the Gaming Commission called the changes “way too little, way too late” and disqualified Plainridge’s application for a gaming license in August 2013. Weeks later, Penn National Gaming reached a deal to pursue a gaming license at Plainridge, with an option to buy the track if its bid were successful. Plainville voters soon approved the slots plan by a margin of 3 to 1 in a town referendum, required as a condition of licensing.

Penn National was awarded the gaming license in February 2014. The slot parlor held a soft opening for guests on June 22, 2015, and opened to the public on June 24. In October 2018, Penn National sold Plainridge’s real estate assets to Gaming and Leisure Properties for $250 million and leased it back for $25 million per year. It is now situated approximately 30 miles southwest of Boston, Massachusetts, in the community of Plainville, owned by Gaming and Leisure Properties and operated by Penn National Gaming.