|Location||Arlington Heights, Illinois|
|Owned by||Churchill Downs Inc.|
|Date opened||October 13, 1927|
|Notable races||Arlington Million (G1)
Beverly D. Stakes (G1)
Secretariat Stakes (G1)
American Derby (G2)
Arlington International Racecourse is a horse race track in the Chicago suburb of Arlington Heights, Illinois. Horse racing in the Chicago region has been a popular sport since the early days of the city in the 1830s, and at one time Chicago had more horse racing tracks (six) than any other major metropolitan area. Arlington International was the site of the first thoroughbred race with a million-dollar purse in 1981. It is located near the Illinois Route 53 freeway.
Arlington International Racecourse was founded as Arlington Park by California businessman Harry D. "Curly" Brown who would later serve as president of Oriental Park Racetrack in Havana, Cuba.  The track officially opened in 1927 to 20,000 spectators. Jockey Joe Bollero, who later became a successful trainer, rode Luxembourg to victory in the first race ever run at Arlington.
Benjamin F. Lindheimer acquired control of Arlington Park in 1940 and owned it until his death in 1960. Long involved with the business, adopted daughter Marjorie Lindheimer Everett then took over management of the racetrack. Widely respected Hall of Fame trainer Jimmy Jones of Calumet Farms was quoted by Sports Illustrated as saying that Lindheimer "was the savior of Chicago racing" and that "Arlington Park became the finest track in the world—certainly the finest I've ever been on."  Benjamin Lindheimer is well remembered as the person who promoted the 1955 match race broadcast by CBS Television in which Preakness and Belmont Stakes winner Nashua defeated Kentucky Derby winner, Swaps.
Arlington was the first track to install a public-address system and employed the pioneering race caller Clem McCarthy to describe the action. It added the first electric totalisator which allowed a credible tote board and decreased time between races, in 1933. In 1936 it added a photo finish camera. It introduced the first electric starting gate in 1940 and the largest closed circuit TV system in all of sports in 1967 (while Arlington is credited in some circles with the introduction of trifecta wagering in 1971, the New York Racing Association first offered the bet, known as "The Triple" a year earlier in 1970 and it was known as that because it was generally only offered on the last race of the day with limited exceptions until 1995 when two were offered by the NYRA tracks and they began using the term trifecta).
In 1981 Arlington was the home of the world's first million dollar thoroughbred race: The Arlington Million. The result of that race is immortalized in bronze at the top of the paddock at Arlington, where a statue of jockey Bill Shoemaker riding John Henry to a thrilling come-from-behind victory over 40-1 long shot The Bart celebrates Thoroughbred racing's inaugural million dollar race.
Arlington entered a new era when Richard L. Duchossois led an Illinois investment group to purchase the track from its former owners and made a pledge to continue presenting championship racing. That was tested on July 31, 1985, when a small fire spread quickly out of control and completely destroyed the grandstand and clubhouse.
Unsure of the future of Arlington, the meet was moved to Hawthorne Race Course. Yet it was announced that the Arlington Million would still be held at Arlington International. On August 25, 1985 they did just that by using temporary bleachers. The track fully reopened in 1989. It briefly used the name "Arlington International Racecourse" before reverting to the old name. Arlington reverted to using Arlington International Racecourse starting in 2013.
In 2000, Arlington reopened after a two-year shutdown. In September of that year, Churchill Downs Incorporated completed its purchase of the track.
Arlington hosted the 2002 Breeders' Cup World Thoroughbred Championships at their track.
On May 14, 2010, Lee DeWyze, a citizen of Mount Prospect, Illinois and a contestant on American Idol, performed a concert at Arlington Park for approximately 41,000 fans. A year later, on May 14, 2011, Haley Reinhart, of Wheeling, Illinois, also made the top 3 on American Idol. She, like DeWyze, had a hometown concert at the track for nearly 30,000 of her own fans and supporters.
The track has a one mile and one-eighth dirt oval and a one mile turf oval. The track is capable of seating at least 50,000 with extension. There is stabling on the backstretch for over 2,000 horses.
Arlington replaced its dirt course with a synthetic track prior to the opening of the 2007 season.
- Caton Bredar (1988–1991) 
- Lynne Snierson (1992–1994)
- Christine Gabriel (1995–1997, 2000–2005)
- John G. Dooley (2000–present)
- Molly Ryan (2006)
- Liane Davis (2006–2007)
- Zoe Cadman (2006–2007)
- Lauren Massarella (2006–2008)
- Joe Kristufek (2006–present)
- Jessica Pacheco (2008–2013)
- Alyssa Ali (2007-2008 fill-in, 2009–present full-time)
- Gabby Gaudet (2014-present)
The following graded stakes are run at Arlington Park:
- Arlington Classic Stakes
- Arlington Handicap
- Arlington Matron Handicap
- Arlington Oaks
- Arlington-Washington Futurity Stakes
- Arlington-Washington Lassie Stakes
- Chicago Handicap
- Hanshin Cup Handicap
- Modesty Handicap
- Pucker Up Stakes
- Sea o'Erin Stakes
- Stars and Stripes Turf Handicap
- Washington Park Handicap
- Arlington Sprint Handicap
- Isaac Murphy Handicap
- Lincoln Heritage Handicap
- Round Table Stakes (on hiatus)
- American 1000 Guineas Stakes
- The Encyclopedia of Chicago (online version)
- Arlington Park: History
- Equibase: North American Thoroughbred Racing Starters: Jockeys