The MSHD started construction in 1936 on a new road that rerouted US 2 into St. Ignace for the first time . Between Brevort and Moran , US 2 previously followed Worth Road inland to the Tahquamenon Trail to meet the northern extension of US 31 into the Upper Peninsula . The new routing took US 2 along the lakeshore into St. Ignace . US 31 was truncated to the state ferry docks in Mackinaw City and US 2 was routed through St. Ignace along the former US 31 to Rogers Park ; the connection in St. Ignace to the state ferry docks became M ‑ 122 . Further changes in the early 1940s straightened the roadway out near Watersmeet and Crystal Falls .