The Roseau River is a 214-mile-long tributary of the Red River of the North that originates in the wetlands of Beltrami Island State Forest and runs north and west across Roseau County before entering Manitoba just west of Caribou in Kittson County. French fur traders named it for reeds and rushes, a fitting name for a river that meanders through common reed, sedges, and rushes along its banks and across large lowland areas. Historically, it was an important trade route for indigenous peoples and early Europeans, linking the Red River Valley and the Dakotas to Lake of the Woods and points east by way of the Red River, the Roseau, Hay Creek, a portage at the sand ridge on present day County Road 12, and the Warroad River. Dakota, or Sioux, and later Ojibwe, or Chippewa, established settlements throughout the Roseau River Valley and used the Red and Roseau Rivers as transportation and trade routes to the wild rice fields around Lake of the Woods. By the mid-1600s the valley had become disputed territory between the two tribes, and a fierce war in the mid-1700s gave it the moniker war-road, from which the present-day City of Warroad derives its name. The Ojibwe ultimately pushed out the Dakota and established small villages throughout the valley, including settlements at present day Ross and Wannaska and along Hay Creek. French explorers arrived as early as 1734, and later French traders established trading posts with native tribes. By the mid-1800s the U.S. Government had moved Ojibwe nations to reservation lands near Lake of the Woods, Red Lake, Leech Lake, and White Earth to open the west to homesteaders, and although most Ojibwe tribal members gave up their homesteads in the valley, a few remained alongside new European neighbors. In the late 1800s, after the Homestead Act of 1862, the first European settlers came in search of farmland and timber, but frequent flooding and extensive wetlands made agriculture difficult. Government leaders then promoted dredging, draining, and channelizing the valley to create more arable land, dramatically altering it from the City of Roseau north and west to the Canadian border; the shoreline remnant of Roseau Lake remains visible on aerial photos, and the last dredging occurred in the 1930s. This agricultural expansion led to the establishment of the village of Roseau, where dams and mills provided power for sawing lumber and milling flour, and as settlement grew, Roseau was incorporated as the Roseau County Seat in 1895.