The Portage River is a 15.5 miles (24.9 km) river in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Michigan

Michigan

Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....

, flowing mostly southwesterly through northeast Jackson County

Jackson County, Michigan

As of the census of 2000, there were 158,422 people, 58,168 households, and 40,833 families residing in the county. The population density was 224 people per square mile . There were 62,906 housing units at an average density of 89/sq mi...

.

The Portage River rises at approximately 42°22′26"N 84°10′48"W in the Portage Lake Swamp in the Waterloo State Recreation Area

Waterloo State Recreation Area

Waterloo State Recreation Area is the third-largest park in Michigan, encompassing over of forest, lakes and wetlands. Located in northeast Jackson County and parts of Washtenaw County, the park is the largest in the Lower Peninsula of Michigan and features 4 campgrounds, 11 lakes, a nature...

. The river flows mostly southwest into the Grand River

Grand River (Michigan)

The Grand River is the longest river in the U.S. state of Michigan. It runs through the cities of Jackson, Eaton Rapids, Lansing, Grand Rapids, and Grand Haven.-Description:...

 at 42°18′54"N 84°23′42"W in Blackman Charter Township

Blackman Charter Township, Michigan

Blackman Charter Township is a charter township of Jackson County in the U.S. state of Michigan. As of the 2000 census, the township population was 22,800. It encompasses most of the survey township T2S R1W....

 just north of the city of Jackson

Jackson, Michigan

Jackson is a city located along Interstate 94 in the south central area of the U.S. state of Michigan, about west of Ann Arbor and south of Lansing. It is the county seat of Jackson County. As of the 2010 census, the city population was 33,534...

. The Portage River forms the boundary between the townships of Henrietta

Henrietta Township, Michigan

Henrietta Township is a civil township of Jackson County in the U.S. state of Michigan. The population was 4,483 at the 2000 census.- History :...

 and Leoni

Leoni Township, Michigan

Leoni Township is a civil township of Jackson County in the U.S. state of Michigan. The population was 13,459 at the 2000 census.- Communities :* Leoni is a small, unincorporated community within the township, several miles east of Jackson....

.

Drainage basin

The Portage River drains all or portions of the following administrative divisions:

• Ingham County
  Ingham County, Michigan
  -Demographics:As of the census of 2000, there were 279,320 people, 108,593 households, and 63,744 families residing in the county. The population density was 500 people per square mile . There were 115,056 housing units at an average density of 206 per square mile...
  
  
  • Bunker Hill Township
    Bunker Hill Township, Michigan
    Bunker Hill Township is a civil township of Ingham County in the U.S. state of Michigan. As of the 2000 census, the township population was 1,979.-Communities:*Bunker Hill Center is an unincorporated community near the center of the township at ....
    
    
  • Ingham Township
    Ingham Township, Michigan
    Ingham Township is a civil township of Ingham County in the U.S. state of Michigan. The population was 2,061 at the 2000 census.-Communities:*The village of Dansville is near the center of the township on M-36 about 7 miles southeast of Mason.-Geography:...
    
    
  • Stockbridge Township
    Stockbridge Township, Michigan
    Stockbridge Township is a civil township of Ingham County in the U.S. state of Michigan. The population was 3,896 at the 2010 census.-Geography:...
    
    

• Jackson County
  Jackson County, Michigan
  As of the census of 2000, there were 158,422 people, 58,168 households, and 40,833 families residing in the county. The population density was 224 people per square mile . There were 62,906 housing units at an average density of 89/sq mi...
  
  
  • Blackman Charter Township
    Blackman Charter Township, Michigan
    Blackman Charter Township is a charter township of Jackson County in the U.S. state of Michigan. As of the 2000 census, the township population was 22,800. It encompasses most of the survey township T2S R1W....
    
    
  • Grass Lake Township
  • Henrietta Township
    Henrietta Township, Michigan
    Henrietta Township is a civil township of Jackson County in the U.S. state of Michigan. The population was 4,483 at the 2000 census.- History :...
    
    
  • Leoni Township
    Leoni Township, Michigan
    Leoni Township is a civil township of Jackson County in the U.S. state of Michigan. The population was 13,459 at the 2000 census.- Communities :* Leoni is a small, unincorporated community within the township, several miles east of Jackson....
    
    
  • Waterloo Township
    Waterloo Township, Michigan
    Waterloo Township is a civil township of Jackson County in the U.S. state of Michigan. The population was 3,069 at the 2000 census.-Geography:...
    
    

• Washtenaw County
  Washtenaw County, Michigan
  Washtenaw County is a county in the U.S. state of Michigan. As of the 2010 census, the population was 344,791. Its county seat is Ann Arbor. The United States Office of Management and Budget defines the county as part of the Detroit–Warren–Flint Combined Statistical Area...
  
  
  • Lyndon Township
    Lyndon Township, Michigan
    Lyndon Township is a civil township of Washtenaw County in the U.S. state of Michigan. The population was 2,728 as of the 2000 census.-Geography:The township is located in the northwest corner of Washtenaw County....
    
    
  • Sylvan Township
    Sylvan Township, Washtenaw County, Michigan
    Sylvan Township is a civil township of Washtenaw County in the U.S. state of Michigan. The population was 6,425 at the 2000 census. The 2008 population estimate is 3,394...
    
    

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