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LakeQuality

Lake Watersheds

Lakes grouped by their drainage basin. We use the USGS Watershed Boundary Dataset (HUC8 "subbasins") for major named systems. Each watershed page lists every monitored lake that drains through that basin, with water quality grades.

Mississippi Headwaters
Minnesota · 477 monitored lakes · HUC8 07010101

The first 400 miles of the Mississippi River from Lake Itasca through the headwaters lakes region — Bemidji, Cass, Winnibigoshish, and dozens of source-water lakes.

St. Croix Watershed
Minnesota + Wisconsin · 361 monitored lakes · HUC8 07030005

The St. Croix River basin straddling the Minnesota–Wisconsin border, one of the cleanest large-river watersheds in the Upper Midwest and a National Scenic Riverway.

Wisconsin River Watershed
Wisconsin · 447 monitored lakes · HUC8 07070005

The Wisconsin River basin from the Northwoods through the Dells to the Mississippi confluence — covers the Northwoods lakes country including Vilas and Oneida counties.

Wolf River Watershed
Wisconsin · 105 monitored lakes · HUC8 04030202

The Wolf River and its tributaries draining northeast Wisconsin into Lake Winnebago — premier walleye and musky country.

Chippewa River Watershed
Wisconsin · 140 monitored lakes · HUC8 07050001

The Chippewa River basin draining north-central Wisconsin, including the Hayward Lakes and Chippewa Flowage — world-class musky destination.

Red River of the North Watershed
Minnesota · 228 monitored lakes · HUC8 09020306

The Red River basin draining western Minnesota north into Lake Winnipeg, Canada. Includes the Red River Valley lakes and the Otter Tail headwaters.

Minnesota River Watershed
Minnesota · 143 monitored lakes · HUC8 07020012

The Minnesota River basin draining southern Minnesota — agricultural country with high phosphorus loading and a classic test case for nutrient-driven lake degradation.

Rum River Watershed
Minnesota · 114 monitored lakes · HUC8 07010207

The Rum River draining from Mille Lacs Lake south to the Mississippi — a State Wild and Scenic River with relatively undeveloped lake country.

Crow River Watershed
Minnesota · 317 monitored lakes · HUC8 07010204

The Crow River system draining central Minnesota agricultural counties — includes the Annandale and Buffalo lakes regions.

Lake Superior Basin (MN+WI)
Minnesota + Wisconsin · 680 monitored lakes · HUC8 04010102

Lakes draining north into Lake Superior across the Arrowhead region of Minnesota and northern Wisconsin — including the Boundary Waters Canoe Area Wilderness lakes.

Lower Fox-Wolf (Lake Winnebago Pool)
Wisconsin · 18 monitored lakes · HUC8 04030204

Lake Winnebago and the Fox-Wolf system in east-central Wisconsin — the largest inland lake in Wisconsin and a major fishery.

Sauk River Watershed
Minnesota · 148 monitored lakes · HUC8 07010202

The Sauk River chain of lakes in central Minnesota — popular cabin and resort destination west of St. Cloud.

Pine River Watersheds (Brainerd Lakes)
Minnesota · 306 monitored lakes · HUC8 07010104

The Pine River and Whitefish chain — Brainerd Lakes country, Gull, Pelican, and dozens of premier MN cabin lakes.

Rainy Lake Watershed
Minnesota · 346 monitored lakes · HUC8 09030001

Rainy Lake and the Vermilion River basin draining north into Hudson Bay via the Rainy River and Lake of the Woods — the BWCA borderlands and Voyageurs National Park.

Sheboygan-Manitowoc
Wisconsin · 36 monitored lakes · HUC8 04030103

Lake Michigan tributaries draining east-central Wisconsin into Lake Michigan via Sheboygan and Manitowoc Rivers.

Watershed boundaries from the USGS Watershed Boundary Dataset. Lake-to-watershed assignment is currently based on county overlap; precise HUC8-polygon spatial joins coming in a future update.