By Tracy Swartz
RedEye
With a week left until the start of the Chicago Marathon's general registration lottery, the marathon and a local pro-charity group are encouraging runners to raise money for charity to get guaranteed entry into the race.

Unlike years past, the marathon is not capping the number entries for charity runners for the Oct. 12 race. About 10,000 of the 45,000 who entered last year ran for causes.

"We encourage all runners to consider running for charity," Kathleen Neuman, a marathon spokeswoman, said in an e-mail.

Requirements for guaranteed charity entry vary between programs. Participants must raise $1,000 if they decide to run before April 7. After April 14, they are required to raise $1,500.

Other runners can register in the general lottery for a non-guaranteed entry between March 5 and April 7. The lottery opens at 12 p.m.

Charity entry is typically a popular route for guaranteeing a race bib. About 190 charities have partnered with the marathon this year, up from more than 140 charities last year.

Courtney Gray, co-director of agoodsport.net, a local startup that helps runners find charities, said she expects charity running to become even more popular because of the expanded system. She posted a graphic to the group's Facebook page to remind runners how they can get guaranteed entries into the race.

"The charity program itself will be much more in the spotlight," Gray said.

In addition to running for charities, U.S. runners can guarantee entry if they have run the Chicago marathon five or more times within the last 10 years, if they have finished in under three hours and 15 minutes (men) or 3 hours and 45 minutes (women), or if they are a wheelchair athlete.

The Chicago Marathon used to have a first come, first serve registration process until last year, when the number of people signing up for the race overwhelmed the registration system. About 25,000 runners were able to register and the rest of the spots were filled by lottery.

The fee to register this year is $185 for U.S. residents and $210 for those outside the U.S.

tswartz@tribune.com