Michigan State Route 231 is a north-south highway in Ottawa County. It runs from Interstate 96, near Nunica, to Michigan State Route 45, near Robison. This serves as a sorta Grand Haven bypass for U.S. Rt. 31; using Interstate 96 and Michigan State Route 45. Plans call for a southern extenstion to Interstate 196 in the future. MI St Rt 231 does not pass through any following town in Ottawa County. MI St Rt 231 is not multi-plexed in Ottawa County. MI St Rt 231 intersects the following highways in Ottawa County. Interstate 96, near Nunica. Michigan State Route 104, near Nunica. Michigan State Route 45, near Robinson.