In 198 days · Sun, Mar 21, 2027
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Sunday, March 21st, 2027
23270 E River Rd, Grosse Ile MI
Half · 15K · 5K
32–47°F · some rain risk
See last 10 years
On this date: rain 0 of the last 10 years
2026
30–41°F
dry
2025
29–51°F
dry
2024
22–33°F
dry
2023
35–47°F
dry
2022
35–54°F
dry
2021
30–50°F
dry
2020
26–34°F
dry
2019
35–48°F
dry
2018
29–39°F
dry
2017
30–55°F
dry
Best months to race in Michigan →
About this race
Race Overview
Rock CF is hitting the island for the 15th Annual Rivers Half Marathon, 5K Run/Walk & NEW 15K!
Rock CF is a community, thousands strong, changing the face of what living with cystic fibrosis looks like and giving those living with CF the tools to not only survive, but thrive. 100% of all proceeds support the mission of the Rock CF Foundation.
Date and Location
- Date: March 21, 2027
- Start Location: Grosse Ile Middle School - 23270 E River Rd, Grosse Ile Township, MI 48138
- Finish Location: Grosse Ile Middle School - 23270 E River Rd, Grosse Ile Township, MI 48138
- Race URL: Register Here
Registration Caps
- Half Marathon Cap: 800
- 15K Cap: 300
- 5K Run/Walk Cap: 500
Half Marathon Details
- Start Time: 8:00am
- Start Location: Grosse Ile Middle School
- Finish Location: Grosse Ile Middle School
15K Details
- Start Time: 8:00am
- Start Location: Grosse Ile Middle School
- Finish Location: Grosse Ile Airport Area
5K Run/Walk Details
- Start Time: 8:15am
- Start Location: Grosse Ile Airport (South of Naval Hangar)
- Finish Location: Grosse Ile Middle School
Virtual Run Option
We will be sending out packets the week of the race so that you can participate with us from wherever you are! Whether that be a walk around the block or a full half marathon, we can't wait to see what you accomplish. Be sure to tag us on our socials @LetsRockCF so we can share your journey and runs!
Course map
Train with a club
Run clubs near Grosse Ile to train with before race day.
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