MARCUS, Iowa — Aug. 21, 2026 — Drivers on Iowa 3 and Iowa 143 should expect to follow a detour to reach Marcus from Monday, Aug. 24, until the end of October, weather permitting, according to the Iowa Department of Transportation's Sioux City construction office.
Crews will be completing the last phase of the roundabout construction at the intersection of Iowa 3 and Iowa 143 by closing Iowa 143.
Please note the following:
- Crews will maintain at least one lane of traffic on Iowa 3. A single lane of traffic will be controlled by temporary traffic lights.
- Cherokee County Road L-36 will remain closed until the project is completed.
- A lane-width restriction of 10 feet and a height-limit restriction of 15 feet will be in place.
During the closure, motorists will follow a marked detour route using the following routes:
- Cherokee/Plymouth County Road C-38
- Plymouth County Road L-22
- Cherokee/Plymouth County Road C-16
- Cherokee County Road L-40
The Iowa DOT reminds motorists to drive with caution, obey the posted speed limit and other signs in the work area, and be aware that traffic fines for moving violations are at least double in work zones. As in all work zones, drivers should stay alert, allow ample space between vehicles, and wear seat belts.
The latest traveler information is available anytime through our 511 system. Visit 511ia.org; call 511 (within Iowa) or 800-288-1047 (nationwide); stay connected with 511 on Facebook or X (find links at https://iowadot.gov/travel-tools/iowa-511/511-social-media-sites); or download the free app to your mobile device.
It’s easy to subscribe to Your 511 and sign up to receive email/text alerts. Visit https://new.511ia.org/#login to sign up. For instructions and help with this feature, visit https://www.511ia.org/help/section/how-to-create-and-manage-a-511-account.html.
###
For more information, contact Sarah Tracy, District 3 transportation planner, at 712-274-5831 or [email protected].