MASON CITY – Northern Iowa motorists who travel U.S. 65 between Rockwell and Sheffield will need to use a detour starting Tuesday, May 26, 2026, as crews begin a bridge replacement project over the West Fork of the Cedar River.
The Iowa Department of Transportation’s Mason City construction office said the closure is expected to remain in place until August 11, weather permitting.
The project will close U.S. 65 to traffic between the Rockwell and Sheffield areas while the bridge is replaced. The DOT’s detour map shows traffic being routed around the work zone through Franklin and Cerro Gordo counties.
During the closure, drivers will be detoured east for about two miles on Franklin County Road C-13 to Franklin/Cerro Gordo County Road S-56. Traffic will then travel north on S-56 for about 11.6 miles to Cerro Gordo County Road B-43, then west about four miles on B-43 to return to U.S. 65.
The closure will affect local commuters, farm traffic, delivery drivers and others who regularly use U.S. 65 as a north-south route between communities in the area. Motorists should plan for extra travel time and watch for detour signs.
The Iowa DOT reminds drivers to use caution near the work zone, obey posted speed limits and signs, and stay alert for workers and construction equipment. Traffic fines for moving violations are at least double in work zones.
Drivers are also urged to allow extra space between vehicles and wear seat belts.
The latest traveler information is available through Iowa DOT’s 511 system at 511ia.org or by calling 511 from within Iowa.