The 17th Annual F^3 Lake Half Marathon & 5k is Chicago's Original Winter Half Marathon. Each year, thousands of runners flock to this community-built event, gathering in the warmth of Soldier Field's United Club before tackling wind & weather along a lakefront course that features splits every 5km. A must for anyone preparing for a spring marathon or just resolving to stay fit throughout the new year. F^3 sold out in 2016-2020 and 2023-present.

Every registrant will once again receive one of our great hoodies and a medal! We will return to the warm confines of Soldier Field's United Club! The UC opens at 8 a.m. Gear check is available. The half marathon starts at 10 a.m. and consists of self-seeded waves in quick succession. The 5k is scheduled for 10:30 a.m. Courses close at 1:30 p.m.

After the race, head to Weathermark Tavern for the afterparty! 1503 S. Michigan Ave. Free participant photos are always uploaded to flashframe.io