The Sunrise River is a short tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the St. Croix River

St. Croix River (Wisconsin-Minnesota)

The St. Croix River is a tributary of the Mississippi River, approximately long, in the U.S. states of Wisconsin and Minnesota. The lower of the river form the border between Wisconsin and Minnesota. The river is a National Scenic Riverway under the protection of the National Park Service. A...

 in east-central Minnesota

Minnesota

Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...

 in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. It is formed at the town of Stacy

Stacy, Minnesota

Stacy is a city in Chisago County, Minnesota, United States, along the Sunrise River. The population was 1,456 at the 2010 census.Interstate 35 serves as a main arterial route for the community.-Geography:...

 in Chisago County by the confluence

Confluence (geography)

In geography, a confluence is the meeting of two or more bodies of water. It usually refers to the point where two streams flow together, merging into a single stream...

 of its West Branch, which rises in southwestern Isanti County

Isanti County, Minnesota

As of the census of 2010, there were 37,816 people, 14,331 households, and 8,415 families residing in the county. The population density was 71 people per square mile . There were 12,062 housing units at an average density of 28 per square mile...

 and briefly enters Anoka County

Anoka County, Minnesota

Anoka County is the fourth-most populous county in the U.S. state of Minnesota. The county is bordered by the counties of Isanti on the north, Chisago and Washington on the east, Hennepin and Ramsey on the south, Sherburne on the west, and the Mississippi River on the southwest.As of 2010, Anoka...

; and its South Branch, which rises in Anoka County and flows through the town of Wyoming

Wyoming, Minnesota

As of the census of 2000, there were 3,048 people, 1,023 households, and 848 families residing in the city. The population density was 1,069.8 people per square mile . There were 1,055 housing units at an average density of 370.3 per square mile...

. From Stacy it flows generally NNW through Chisago County to meet the St. Croix, within Wild River State Park

Wild River State Park

Wild River State Park is a state park of Minnesota, USA, curving along of the St. Croix River. This long, narrow park is shaped somewhat like a sideways 'S', with development largely concentrated in the lower third. The remote upper sections flank the mouth of a tributary called the Sunrise...

. Not far upstream from its mouth, the Sunrise collects its North Branch, which rises in Isanti County and flows through the town of North Branch

North Branch, Minnesota

As of the census of 2000, there were 8,023 people, 2,815 households, and 2,147 families residing in the city. The population density was 224.9 people per square mile . There were 2,900 housing units at an average density of 81.3 per square mile...

.