Belmont Park is a Thoroughbred horse racetrack in Elmont, New York, United States, just east of New York City limits. Opened on May 4, 1905, it is one of the most well known racetracks in the country, as it hosts the Belmont Stakes, the final leg of the American Triple Crown. The original structure was demolished in 1963, and a second facility opened in 1968. The second structure was demolished in 2024, and a third version of Belmont Park is expected to open in 2026.

Operated by the New York Racing Association (NYRA), Belmont Park is typically open for racing from late April through mid-July (known as the Spring meet), and again from mid-September through late October (the Fall meet). The race park's main dirt track has earned the nickname, "the Big Sandy", given its prominent overall dimensions (1+1⁄2 miles (2.4 km)) and the deep, sometimes tiring surface. Belmont is also sometimes known as "The Championship Track" because almost every major champion in racing history since the early 20th century has competed on the racecourse – including all of the Triple Crown winners. Belmont Park, with its large, wide, sweeping turns and long homestretch, is considered one of the fairest racetracks in America.

Belmont hosted its largest crowd at the 2004 Belmont Stakes, when 120,139 spectators saw Smarty Jones upset by Birdstone in his Triple Crown bid.

August Belmont Jr. and William Collins Whitney, along with other investors, built the original Belmont race track, which opened on May 4, 1905. Arthur Underhill was hired as Engineer and Landscape Architect to design and oversee construction of the park. In its first 15 or so years, Belmont Park featured racing clockwise, in the "English fashion"—allowing the upper-class members of the racing association and their guests to have the races finish in front of the clubhouse, just to the west of the grandstand. A "field stand," at what was then the top of the stretch, was located east of the grandstand. The original finish line was located at the top of the present-day homestretch. In his 1925 book, "The Big Town", Ring W. Lardner refers to the then-recent directional change when he has a character at Belmont say (speaking of a recent race) "At that time, they run the wrong way of the track, like you would deal cards".

A later innovation was created by Joseph E. Widener, who took over track leadership when August Belmont II died in 1924: the Widener Chute. It was a straightaway of just under 7 furlongs (1.4 km) that cut diagonally through Belmont's training and main tracks, hitting near the quarter-pole of the main track; the course was removed in 1958.

Two features of the original Belmont Park remain today. The first is the display of four stone pillars on Hempstead Turnpike, a gift from the mayor and park commissioners of Charleston, South Carolina. The pillars had stood at the entrance of the Washington Course of the South Carolina Jockey Club in Charleston, which operated from 1792 to 1882. The stone pillars are now found at the clubhouse entrance. Lesser known but more visible are the racing motif iron railings seen partially bordering the walking ring. The railings, used as decoration on the south side of the old Belmont grandstand, were salvaged during the 1963 demolition.

The original Belmont Park was not only unprecedented in its size but also had the then-new innovation of a Long Island Rail Road extension from the Queens Village station, running along the property, tunneling under Hempstead Turnpike, then terminating on the south side of the property. The train terminal was moved to its present location north of the turnpike after the 1956 season.

Near the railroad terminal was yet another track—Belmont Park Terminal, a steeplechase course operated by United Hunts until 1927.