Lime Rock Park is a natural-terrain motorsport road racing venue located in Lakeville, Connecticut, United States, a hamlet in the town of Salisbury, in the state's northwest corner. Built in 1956, it is the nation's third oldest continuously operating road racing venue, behind Road America (1955) and Willow Springs International Motorsports Park (1953). The track is owned by Skip Barber, a former race car driver who started the Skip Barber Racing School in 1975. It was listed on the National Register of Historic Places in 2009.
The 1.53-mile Lime Rock track was originally conceived of in 1956 by Jim Vaill, who, along with John Fitch and Cornell Aeronautical Laboratory, built the track utilizing state-of-the-art road and highway safety principles of the time. The first race, a mix of G-Production class and an MG class, was held on April 28, 1957. The winner of the G-Production was Ted Sprigg in an Alfa Romeo Giulietta. The winner of the MG class was Charles Callanan in an MG TC. In 1959, Lime Rock hosted the Little Le Mans race, won by Charles Callanan and Roger Penske in a Fiat Abarth. In 2008, the track was re-paved and two new corner complexes were added.
The track has a loyal following, though it did face some resistance from the local community shortly after it opened. In 1959, the Lime Rock Protective Association, with support from the nearby Trinity Episcopal Church, took the park to Litchfield Superior Court in an effort to ban Sunday racing. The court issued a permanent injunction against Sunday racing, and its decision was upheld by the Connecticut Supreme Court. While restrictive, the carefully crafted injunction was also enabling. It preserved the track's right to conduct unmuffled sports car racing on Fridays and Saturdays, plus testing on Tuesdays and other operating benefits. The injunction stands to this day.
The track has featured many well-known racers including Paul Newman, who supported his own Newman-Haas team with Bob Sharp, Mario Andretti, Stirling Moss, Dan Gurney, Sam Posey, and Mark Donohue. Other racers have included Parnelli Jones, Joey Logano, Austin Dillon, Simon Pagenaud, Alexander Rossi, and Tom Cruise.
The track is a natural terrain road course, constructed over hilly terrain in the Berkshire Mountains, part of the greater Appalachian mountain range. The famous Appalachian Trail hiking route passes by the circuit on the ridge lines visible from the track a half mile to the east. The venue is somewhat unique in that it features no grandstands or bleacher seating, instead inviting fans to bring chairs and blankets and enjoy the racing from its grassy hillside areas under the shade of trees. While generally regarded as a minor player on the US road racing scene, the relatively short track is renowned for its spectator experience, offering fans an up close view and close quarters racing.  
For years the track was listed as being 1.53 miles in length—the story goes that right after it was built, somebody used the odometer in a Chevrolet to measure the track length—and 1.53 was taken as gospel. Following the 2008 reconstruction (see below), Lime Rock's operations people measured all four possible configurations, and as it turns out, each was 1.5 miles long, plus or minus a few hundred feet. The IMSA Weathertech Sportscar Championship gives the distance of the track as 1.474 miles. The "classic" configuration is seven turns, while the three optional layouts are eight, nine and ten turns, respectively.
- Formula Atlantic
- Formula Libre
- Grand-Am Continental Tire Sports Car Challenge (2006-2013)
- Lime Rock Grand Prix
- NASCAR K&N Pro Series East (1993-2010)
- NASCAR Whelen Modified Tour (2010-2011)
- North American Touring Car Championship (1996)
- Northeast Grand Prix
- Pirelli World Challenge (1992–1993, 1995-2005, 2007–2008, 2013, 2016-2018)
- SCCA Continental Championship Formula 5000 (1968-1972)
- SCCA National Sports Car Championship (1958-1964)
- Trans-Am (1967-1974, 1981, 1985-1989, 1992-1993, 1995-1999, 2002-2003, 2010, 2012-2015, 2019, 2021-present)
- "National Register Information System". National Register of Historic Places. National Park Service. July 9, 2010.
- "The View From Lime Rock: Neighbors learn to live with the noise". New York Times. June 25, 1989. Retrieved 2017-02-13.
- "About Us". Lime Rock Park. Retrieved 2014-03-19.
- "Archived copy". Archived from the original on 2014-05-08. Retrieved 2013-07-07.CS1 maint: archived copy as title (link)
- Lime Rock Park Floats Idea of Renewed Sunday Racing- Lakeville Journal – December 8, 2005
- Crudele, John (January 18, 2011). "Newman's own will not enough to find a way". New York Post.
- Racer Staff (January 24, 2019). "Bertil Roos set for Lime Rock Park return". racer.com. Retrieved January 25, 2019.
- Sinclair, Adam. "From Agony To Ecstasy Robichon Recalls 2019 Lime Rock Win". Speedway Digest. Retrieved 22 July 2021.
- Learner, Preston. "Lime Rock Park: the rescued racing venue with a rich sporting history". Motor Sport Magazine. Retrieved 22 July 2021.
- "Trans Am Racing Returns To Lime Rock Park | Lime Rock Park". limerock.com. Retrieved 2018-09-20.
- "Trans Am - America's Road Racing Series". gotransam.com. Retrieved 2021-07-06.
- Lime Rock Park website
- Documentary by Chris Szwedo
- Skip Barber Racing School (Uses Macromedia Flash)
- Lime Rock Park archive at Racing-Reference