Opened August 2, 1864 with the highlight race of course being the Travers.
Small article on the history:
Like much of history, the early days of the founding of Saratoga are somewhat foggy. John "Old Smoke" Morrissey, a former bare-knuckles boxing champion, bouncer, gambler and U.S. congressman, held a four-day experimental meeting at Horse Haven in Saratoga Springs in 1863. Morrissey was described as a "bully politician, head of a New York City gang called the Dead Rabbits, which -- with clubs and fists -- electioneered for Tammany Hall."
The meeting was so successful that it was decided to build a racetrack across the street from Horse Haven. Official history records that William R. Travers and John Hunter were the masterminds behind the building of Saratoga Race Course in 1864.
It is generally agreed that Morrissey, with his string of gambling houses, put up the money to build Saratoga, but discreetly withheld his name from all official documents. Travers and Hunter were men of prestige and position, and that was very important to getting racing accepted at the time.
The inaugural meeting at Saratoga was short and sweet. The Travers Stakes was the highlight of the meeting, being named, of course, for one of the track's founders and its first president. That Travers and Hunter co-owned the first winner, a colt named Kentucky, of the race named for Travers is not as unusual as it might first seem. In the 1800s, the men who built racetracks were often the ones who bred and owned many of the best horses at these meetings. They built tracks to showcase their horses more than to make money.
http://horseracing.about.com/library/blhandt.htm