Portsmouth Unit
Portsmouth Unit is a state park in Crow Wing County. 8 graded lakes are within 15 miles of the park, including Serpent Lake, Agate Lake, Island Lake.
Portsmouth Unit State Park spans an unrecorded acreage acres in Minnesota — a designated recreation destination with the full set of facilities the state park system provides. The park is paired with 8 graded lakes nearby — enough for a multi-lake visit. Average grade among them: B.
For visitors planning around water quality, the nearby-lakes list below is the practical tool: a park is only as good as the lake you intend to use it from, and the LakeGrade for that lake gives you the water-clarity, nutrient, and algal-pressure context you need.
Nearby Graded Lakes (within 15 mi)
Lakes closest to Portsmouth Unit, weighted by size. Click a lake for its full water quality grade, fish species, and depth.
| Lake | County | Grade | Surface Area | Distance |
|---|---|---|---|---|
| Serpent Lake | Crow Wing | A | 1,116 acres | 1.9 mi |
| Agate Lake | Crow Wing | B | 187 acres | 2.8 mi |
| Island Lake | Crow Wing | A | 126 acres | 3.5 mi |
| Little Rabbit Lake | Crow Wing | B | 172 acres | 4.2 mi |
| Upper Mission Lake | Crow Wing | A | 882 acres | 6.3 mi |
| Lower Mission Lake | Crow Wing | C | 732 acres | 6.5 mi |
| Sagamore Mine Lake | Crow Wing | A | 119 acres | 4.6 mi |
| Hay Lake | Crow Wing | B | 52 acres | 3.8 mi |
Other Parks in the Area
- Cuyuna Country State Recreation Area— State Recreation Area, 0.3 mi
- Mahnomen Unit— State Park, 1.6 mi
- Yawkey Unit— State Park, 1.6 mi
- Sagamore Unit— State Park, 4.5 mi
Where to stay near Portsmouth Unit
Compare cabins, hotels, and vacation rentals near Portsmouth Unit — find a place to stay close to the park and its nearby lakes.
Top-rated places to stay near Portsmouth Unit
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip to Portsmouth Unit?
Get lake water-quality report cards plus the best cabin & lodging deals near Portsmouth Unit — straight to your inbox. No spam, unsubscribe anytime.
Source: EPA National Aquatic Resource Surveys, 2026.