The Chicago Marathon is one of the six World Marathon Majors and is surpassed only by New York and Boston marathons in the U.S. It is also an IAAF Gold Label race and the fourth largest race by the number of finishers worldwide.
The Chicago Marathon is held every year on either the first or second Sunday of October. The first race in the current format was held on September 25, 1977, with 4,200 runners participating. In the recent years, there have been ten times more—about 45,000 participants. Since 2008, the race has been sponsored by Bank of America and is called the Bank of America Chicago Marathon.
The course terrain of the Chicago marathon is quite flat. The race starts and finishes in Grant Park. It is quite picturesque and goes through 29 of the city's neighborhoods. The course is divided into three sections: North, West, and South. Near each of these sections lie three of the city's main stadiums and are nearby the crossroads of these sections. Wrigley Field is near the north. The United Center is to the west. US Cellular Field is to the south. Runners pass Chicago's downtown area and enjoy overwhelming support from locals and volunteers. About 1.7 million Chicagoan spectators come out to watch the marathon and cheer on the runners. Ever since the marathon has been taking place in Chicago, four world and seven national records have been set.