F3 Half Marathon 2025. Over the past nine years, runners have experienced all sorts of weather, and in the tenth year,. The 16th annual f^3 lake half marathon & 5k is set to take place in chicago, featuring a scenic lakefront course that attracts thousands of runners each year.
The half marathon will have a seeded start and will be timed as per normal. The 16th annual f^3 lake half marathon & 5k is chicago’s original winter half marathon.