The speedway was conceived in late 1937 when car owner Emmett Shelley persuaded Roy Richwine, who owned Williams Grove Park across the street, to build a racing facility on adjacent land. The first race was held on May 21, 1939, and was won by Tommy Hinnershitz. Early competition ran under the sanction of the American Automobile Association, featuring big-car and motorcycle classes. The track briefly shut down during World War II from 1942 until 1945, then returned to action with immediate infrastructure upgrades including lights for night racing, a pedestrian tunnel at turn one, and a distinctive bridge spanning the backstretch.
In 1972, Morgan Hughes purchased the speedway from Jack Gunn, establishing the family ownership that continues today. When Morgan Hughes died in 2008, the track passed to his daughter Kathleen to operate.
Post-war racing at Williams Grove was headlined by open-wheel competition under AAA and, from 1956, United States Auto Club (USAC) sanction. Championship cars appeared annually through 1959 for the Indianapolis Sweepstakes race. Stock cars also visited, including a NASCAR Grand National appearance in 1954. The 1949 American Championship Car Racing National Championship drew a large crowd to the track, won by Johnny Mantz. The dominant driver of this era was Tommy Hinnershitz, who won frequently and became the first hero of The Grove.
On October 20, 1963, the National Open was born, billed as the "Biggest Race in the East." Gordon Johncock, a future two-time Indianapolis 500 winner, was the inaugural victor. The decade saw radical evolution in car design, with full-sized coupes giving way to narrowed and lightened Super Modifieds, then to the tubular-framed integrated roll-cage Sprint car that has dominated the sport for more than fifty years since. Ray Tilley set a Williams Grove record with 21 wins in the 1966 season, a mark that still stands.
Modern Sprint Car racing and Late Models became the weekly divisions throughout the 1970s. The rival traveling series the World of Outlaws and the All-Star Circuit of Champions began scheduling regular appearances at the track, intensifying competition with the home-based talent. This rivalry gave rise to the term Pennsylvania Posse for the resident Central Pennsylvania drivers who consistently challenged the Outlaws' national stars such as Steve Kinser and Sammy Swindell. The World of Outlaws Late Model Series debuted in 1988, with its first race held at Williams Grove and won by Larry Phillips. The 358 cubic-inch sprint car class was added as a weekly division in 1989, providing a development ladder beneath the premier 410 class.
A younger generation of drivers — Fred Rahmer, Lance Dewease, Don Kreitz Jr., Greg Hodnett, and Todd Shaffer — came to define the Posse identity. Pennsylvania Speedweek, a week-long multi-track championship, launched in 1991 with Williams Grove hosting the opening round, won by Steve Smith. The speedway expanded to two nights of racing per week in 2006, adding a Saturday Night Series on April 15 of that year when it absorbed divisions from the closing Silver Springs Speedway.
The National Open grew into a three-day event in 2015, further cementing its status as one of the most lucrative sprint car weekends on the calendar. In 2011 the Morgan Cup challenge was established, pitting the World of Outlaws against the Pennsylvania Posse at Williams Grove annually, with the winning faction holding the trophy for the year. Fred Rahmer, the track's all-time winningest driver, retired in 2013 after claiming his first National Open.
Fred Rahmer holds nine Williams Grove point championships, the most in track history, claimed between 1997 and 2013. Lance Dewease holds the most modern-era feature wins. Steve Smith set a record of six consecutive wins in 1976. The fastest single lap under the post-weight-limit era belongs to T.J. Stutts at 16.089 seconds, set in April 2023. The youngest winner in the 410 sprint car division is Gio Scelzi, who won at sixteen years and ten months of age.
Williams Grove Speedway has been represented in video game racing simulations including Dirt Track Racing 2, Dirt Track Racing: Sprint Cars, and World of Outlaws: Sprint Cars 2002. The track's distinctive half-mile Pennsylvania-style layout, with its long straightaways and tight corners, makes it a distinctive challenge in the sim racing environment and has been included as a content track in iRacing.
Williams Grove Speedway stands as one of the defining venues in American short-track and sprint car racing, having shaped the Pennsylvania Posse identity and served as a stage for the sport's most celebrated rivalries. Its National Open remains a benchmark event, drawing national touring series talent into direct competition with the region's best. Entering its ninth decade of operation, the track continues weekly racing from March through October, maintaining an unbroken link to the origins of American oval racing.