A trunk highway in Western Minnesota will be relocated this fall. Highway 67 provides access to Upper Sioux Agency State Park, but is otherwise a relatively unimportant road, carrying only 465 vehicles per day. There had been a road along the route since the wagon travel days, although the original road went straight up the bluff into what is now the park. Upon rebuilding after its addition to the trunk highway system in the great expansion of 1933, it skirted the edge of the bluff, enabling a much more gradual climb.
At a pinch-point between the Yellow Medicine river and the Minnesota River, fill was dumped onto the slope between the bluff and the river to build it up and level it out. In 2019 this portion of highway along the river suffered a major slope failure that was not immediately repairable.
Upon the slope failure, through traffic was detoured onto MN 274 and County State Aid Highway 18 (CSAH 18) pending a study to determine what it would take to fix the road. The study found the root of the problem was the soils underneath the fill being undermined by the Yellow Medicine River. Rather than building a retaining wall or something else, repairing it would have involved removing all the fill to get access to the soils underneath, replacing and stabilizing them, and then putting the fill back.
This would cost $30 million, a staggering amount relative to how little traffic uses the road. With rebuilding the highway cost prohibitive relative to how few motorists would benefit, other options were considered. During the brainstorming phase, the option of rerouting the highway through the park was presented. But that option was discarded quickly due to the impacts a road built to trunk highway standards would have on the park. So the decision was made to reroute MN 67 permanently, adding about 2 minutes of travel time for through traffic.
The options were the temporary detour route of CSAH 18, or CSAH 2 or CSAH 10. The option of CSAH 10 was rejected since it required more mileage and a new river bridge to the trunk highway system. CSAH 2 was chosen for the permanent reroute instead of CSAH 18 due to the better condition of the infrastructure along that road (CSAH 18 has an old timber bridge), better sight lines at the two intersections where the trunk highway will make 90-degree turns and lack of clear local preference for CSAH 18. With this decision, the detour route was shifted to CSAH 2 with temporary signage.
Old MN 67 and the little bit of MN 274 that is not overlapped will be turned back to the county, except for the stretch from Granite Falls to the park. Official jurisdiction changes and the installation of permanent signs will occur this fall, and will include a $11.6 million payment to Yellow Medicine County to accept jurisdiction of the bypassed section of MN 67 southeast of the park and a small section of MN 274 in Wood Lake that will not be replaced by the rerouted MN 67.
For now, there’s a long 20-mile detour to access the campground by vehicle from the rest of the park, but the plan is to build a connecting road within park property. This will be less disruptive to the park as it doesn’t need to meet the same geometric standards as a trunk highway, probably narrow and steep and possibly even gravel. The bridge over the Yellow Medicine River, which also has structural issues due to bad soils, will be removed in 2026. It currently only serves the park campground and one private landowner, who will likely be granted an easement to access the property via the park campground road.
Here are some of my photos from my trip back in June to check out the area.
this is fascinating. Thanks, Monte, for the detailed explanations and photos.
Probably a sign of things to come, with increasing rainfall and erosion due to climate change.