The Border-to-Border Trail (B2B) is a non-motorized pathway that connects cities, parks, and many destinations throughout Washtenaw County. More than 40 miles of trail exist as a part of the B2B today, with 70 miles planned. Sometimes called "The Huron River Greenway". Originally conceived as a trail to go from one side of Washtenaw County to the other, this route starts in Belleville, Michigan, and ends in Lyndon Township outside Chelsea, Michigan.
This trail is also bikeable, but with a max speed of 15mph for bicycling, is much better suited for running or hiking FKT route.
An up to date map is at: https://gisappsecure.ewashtenaw.org/public/ParkFinder/