The section of M-66 north of the US 131 split had the highway's lowest AADT levels in the 2009 survey. MDOT reported that only 1,500 vehicles use this stretch of road in 2009. Of these vehicles, only were 140 trucks that used the segment of highway in 2009. The highway meanders through more forest lands through the community of Green River to East Jordan. M-66 follows Lake Street and turns to follow the western shore of the South Arm of Lake Charlevoix. The roadway turns inland through Ironton before returning to the lakeshore the rest of the way to Charlevoix. M-66 ends at an intersection with US 31 south of downtown next to Lake Michigan.