The Jordan River is a 24.9-mile-long stream in the northwestern part of the lower peninsula in the U.S. state of Michigan. It is the largest tributary of Lake Charlevoix. The Jordan's headwaters rise from springs in the upper Jordan River Valley northeast of Mancelona in Antrim County. The Jordan River was the first river to be designated in Michigan's Natural River…The Jordan River is a 24.9-mile-long stream in the northwestern part of the lower peninsula in the U.S. state of Michigan. It is the largest tributary of Lake Charlevoix. The Jordan's headwaters rise from springs in the upper Jordan River Valley northeast of Mancelona in Antrim County. The Jordan River was the first river to be designated in Michigan's Natural Rivers Program.