Portage River (Jackson County, Michigan)

The Portage River is a 15.5 mi river in the U.S. state of Michigan, flowing mostly southwesterly through northeast Jackson County.

The Portage River rises at approximately 42.37389°N, -84.18°W in the Portage Lake Swamp in the Waterloo State Recreation Area. The river flows mostly southwest into the Grand River at 42.315°N, -84.395°W in Blackman Charter Township just north of the city of Jackson. The Portage River forms the boundary between the townships of Henrietta and Leoni.

Drainage basin
The Portage River drains all or portions of the following administrative divisions:
 * Ingham County
 * Bunker Hill Township
 * Ingham Township
 * Stockbridge Township
 * Jackson County
 * Blackman Charter Township
 * Grass Lake Township
 * Henrietta Township
 * Leoni Township
 * Waterloo Township
 * Washtenaw County
 * Lyndon Township
 * Sylvan Township

Named tributaries
From the mouth:
 * (right) Wildcat Creek
 * Brill Lake
 * (right) outflow from
 * St. John Lake
 * Eagle Lake
 * Mud Lake
 * (left) Batteese Creek
 * Batteese Lake
 * Hewes Lake
 * (left) Orchard Creek
 * (left) Cahaogan Creek
 * (right) Thornapple Creek
 * (left) Pickett Drain
 * Standish Lake
 * (right) Jacobs Lake Drain
 * Jacobs Lake
 * (right) outflow from Portage Lake
 * Little Portage Lake
 * (right) outflow from series of lakes and small streams including
 * Locker Lake
 * Riley Lake
 * Notten Lake
 * Lehman Lake
 * (left) Honey Creek
 * Portage Lake Swamp