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LakeQuality
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Hasbrook Lake

Oneida County, WisconsinOligotrophic

On the LakeGrade rubric, Hasbrook Lake pulls an A: clarity at 68.9 ft and 10 µg/L of phosphorus put it in the top bracket for Wisconsin. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

A TSI value of 27 puts Hasbrook Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. Hasbrook Lake is unusually deep for Wisconsin at 50 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. Hasbrook Lake covers 307 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Hasbrook Lake ranks 36 of 140 in Oneida County — solidly in the upper half of the local distribution.

Eurasian watermilfoil is established at Hasbrook Lake, which can dampen recreational access and pressure the native plant community. Walleye are documented at Hasbrook Lake, one of 5 fish species on record for the lake. A documented public access point at Hasbrook Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-31. Grade methodology: LakeGrade methodology.

Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Crystal clear, you can see 68.9 ft down. Phosphorus level: 10.3 µg/L. Trophic State Index: 27.

MetricValueGrade
Water Clarity (Secchi Depth)68.9 ftA
Phosphorus10.3 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)27Oligotrophic

Low nutrients, clear water, excellent for swimming

Lake Details

CharacteristicValue
Maximum Depth50 ft
Surface Area307 acres
Public AccessYes

Fish Species

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

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

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

Hasbrook Lake fishing regulations (limits, seasons, special rules)

Invasive Species

Chinese Mystery SnailEurasian Water-MilfoilPurple LoosestrifeRusty Crayfish

Water Quality Trend: Improving

Based on 7 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Stable-0.143 m/yr7
Phosphorus Improving-0.7 µg/L/yr5
See year-by-year chart →

Recreation & Access

1
Boat Landings
Yes
Public Access

Location

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County Ranking

Ranked #36 of 140 lakes in Oneida County

Nearby Lakes in Oneida County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1990. 1 station on file (most recent sample 2025).

DNR Assessment
Excellent · Deep Seepage lake
Trophic State Index 33 (oligotrophic) · 5-year average

Fish Species (DNR-rated)

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

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Fish and recreation data from Wisconsin DNR Lakes

Most recent sample: 2025-08-31

Monitoring stations: 1