The race began in Jackson Park and took runners along DuSable Lake Shore Drive and looped them back to the South Side.
Everyone has a different reason for why they are choosing to challenge themselves with a half marathon.
Many trained hard just for this while others are using this race as a training event for the full Bank of America Chicago Marathon next month.
The half marathon kicked off at 7a.m. and the 5K at 7:45 a.m.
The race will take off and finish near East Hayes Drive at 63rd Street and Richards Drive.
DuSable Lake Shore Drive between 31st and 67th Street will be closed at 6 a.m. on Sunday.
Street closures began on Saturday on E Hayes Drive from DuSable Lake Shore Drive to Cornell and S Richards Dr from Hayes to Marquette at 8 a.m.
Additional street closures on Sunday include, according to OEMC:
-Cornell from Hayes to Marquette - 6 a.m.-9 a.m.
-E Marquette Dr from South Stony Island Ave to Cornell - 6 a.m.-8:30 a.m.
-E Marquette Dr from Cornell to DuSable Lake Shore Drive - 6 a.m. - 11:45 a.m.
-Northbound DuSable LSD from Marquette to McCormick Place - 6 a.m.-10 a.m.
-Southbound DuSable LSD from Marquette to 31st St- 6 a.m.-11:30 a.m.
-E 47th St from DuSable LSD to Cornell - 6 a.m. - 10:45 a.m.
-E 57th Dr from DuSable LSD to Everette Ave - 6 a.m.-11 a.m.
-E Science Dr from DuSable LSD to the parking lot - 6 a.m.-11 a.m.
-Michigan Ave from Randolph to Adams curb lane closure from 4 a.m.- 6 a.m.