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Little Round Lake

Sawyer County, WisconsinOligotrophic

Little Round Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

The lake's low TSI puts it in oligotrophic territory — the cleanest of the four trophic classes, but also the most vulnerable to nutrient-driven shifts. Little Round Lake reaches 38 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 179 acres, Little Round Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Within Sawyer County's 50 graded waters, Little Round Lake sits at rank 3, near the top of the local distribution.

Eurasian watermilfoil is established at Little Round Lake, which can dampen recreational access and pressure the native plant community. Walleye are documented at Little Round Lake, one of 6 fish species on record for the lake. Multiple sampling years from the Wisconsin DNR Citizen Lake Monitoring Network back the grade, so the letter should hold steady absent a major watershed shift.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-04. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Crystal clear, you can see 17.3 ft down. Phosphorus level: 12 µg/L. Chlorophyll-a: 1.4 µg/L. Trophic State Index: 37.

MetricValueGrade
Water Clarity (Secchi Depth)17.3 ftA
Phosphorus12 µg/LA
Chlorophyll-a (Algae)1.4 µg/LA
Trophic State Index (TSI)37Oligotrophic

Low nutrients, clear water, excellent for swimming

Lake Details

CharacteristicValue
Maximum Depth38 ft
Surface Area179 acres

Fish Species

Click a species to see all Wisconsin and Minnesota lakes where it is found.

→ Best fishing times for Little Round Lake (14-day solunar calendar)

→ Is it safe to eat fish from Little Round Lake? (mercury & PFAS guide)

Little Round Lake fishing regulations (limits, seasons, special rules)

Invasive & Introduced Species

Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.

Eurasian Water-Milfoil

Water Quality Trend: Improving

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.561 m/yr6
Phosphorus Declining+0.5 µg/L/yr5
Chlorophyll-a Improving-0.1 µg/L/yr2
See year-by-year chart →

Location

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County Ranking

Ranked #3 of 50 lakes in Sawyer County

Nearby Lakes in Sawyer County

Oligotrophic Lakes in Wisconsin

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2025. 2 stations on file (most recent sample 2025).

Fish Species (DNR-rated)

Panfish(Common)Largemouth Bass(Common)Northern Pike(Common)Musky(Present)Smallmouth Bass(Present)Walleye(Present)

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2025-08-04

Monitoring stations: 2