JEFFERSON, Iowa – May 16, 2025 – If you travel near the Interstate 35 and U.S. 20 interchange in Hamilton County you need to be aware of some nighttime road closures that may slow down your trip, according to the Iowa Department of Transportation’s Jefferson construction office.
Crews need to replace several sign trusses at the I-35 and U.S. 20 interchange. To complete this project, crews will be closing the roadway under each of the trusses to safely and efficiently get the old ones removed and the new ones installed. When the roadway is closed portable message signs will be in place to assist you in traveling around the road closures.
Southbound I-35
- Crews will close southbound I-35 from Hamilton County Road D-25 (exit 144) to the I-35 and U.S. 20 interchange (exit 142) at 8 p.m. on Tuesday, May 20, until 6 a.m. Wednesday, May 21, weather permitting.
- When southbound I-35 is closed (see map) you will exit at Hamilton County Road D-25 (exit 144), travel west to U.S. 69, travel south to U.S. 20, then drive east on U.S. 20 to reach southbound I-35.
Eastbound U.S. 20
- Starting at 7 p.m. on Wednesday, May 21, until 6 a.m. on Thursday, May 22, weather permitting, crews will close eastbound U.S. 20 from U.S. 69 (exit 149) east to the U.S. 20 and I-35 interchange (exit 153).
- During this road closure (see map) you will exit U.S. 20 at U.S. 69 (exit 149), travel south on U.S. 69 to Hamilton County Road D-41, travel east to I-35 (exit 139), turn left onto northbound I-35, then exit onto eastbound U.S. 20 at the I-35 and U.S. 20 interchange (exit 142A).
Northbound I-35
- Crews will close northbound I-35 from Hamilton County Road D-41 (exit 139) to the I-35 and U.S. 20 interchange (exit 142A) from 8 p.m. on Thursday, May 22, until 6 a.m. on Friday, May 23, weather permitting.
- When northbound I-35 is closed you will follow a marked detour route (see map) by exiting I-35 at Hamilton County Road D-41 (exit 139), travel east to Hamilton County Road R-77, turn left and travel north to U.S. 20 where you will travel west to reach northbound I-35 (exit 153B).
If weather delays one of these road closures, it will be scheduled for next night. No closures will occur from the evening of Friday, May 23 through Monday, May 26. Any rescheduled road closures will begin on the evening of Tuesday, May 27.
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For general information about this project contact Jenny Hoskins, Iowa DOT Jefferson construction office, at 515-386-8166 or jenny.hoskins@iowadot.us