02/06/2012 03:50 pm ET | Updated Feb 06, 2012

Chicago Marathon Sold Out: 2012 Bank Of America Marathon Sells Out In Just 6 Days

The 2012 Bank of America Chicago Marathon sold out Monday -- just six days after registration began.

“Enthusiasm to run the Bank of America Chicago Marathon is at an all-time high with record breaking interest, and we plan to match that level of enthusiasm by providing participants with a first-class race experience at the 35th anniversary event,” Bank of America Chicago and Illinois Market President Tim Maloney said in a statement.

Last year, the marathon sold out in 31 days. As of Monday afternoon, the maximum 45,000 participants registered for the 2012 event. According to organizers, the 2003 event took 35 weeks to sell out.

Chicago's marathon is popular among marathon runners from around the globe. The city's flat terrain and often cool, early October weather attracts runners hoping to set their personal best finishing times.

“What a way to begin the 35th anniversary Bank of America Chicago Marathon with our field filling up in record time. It is truly a testament to the first-class experience we provide to each and every runner on the streets of Chicago,” Bank of America Chicago Marathon Executive Race Director Carey Pinkowski said in a statement. “This marks the start of an exciting journey for the participants, as well as for our partners in the community, the City of Chicago, our sponsors and our volunteers."

Those hoping to run the October 7 race can still get involved through the marathon's charity program. More than 90 nonprofits have entries available for the 2012 race. Learn more about the charity program here.