Racing has run at Saratoga Race Course on Union Avenue since 1863. Opened in 1863, this track is often considered to be the oldest major sporting venue of any kind in the United States, and yet it is the fourth oldest racetrack overall, after Fair Grounds Race Course in New Orleans (1838), Freehold Raceway (1854, closed 2024), and Pleasanton Fairgrounds Racetrack (1858). The course is operated today by the New York Racing Association.
Its racing meet began very modestly—originally lasting only four days—and was lengthened gradually. From 1962 to 1990 the meet ran for four weeks and began in late July or early August; in 2010 it expanded to 40 racing days with races five days per week, and now runs from mid-July through Labor Day in early September. The place’s roots go even deeper: Saratoga Springs hosted "trials of speed and exhibition of horses" at county fairs as early as 1822, and in 1847 the Saratoga Trotting Course was built, staging its first harness race on August 14.
You can find the old harness track's ground just south of today's Oklahoma Track, where the Saratoga Trotting Course staged its first harness race on August 14, 1847.