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LakeQuality
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Hemlock Lake

Oneida County, WisconsinLimited DataOligotrophic

On the LakeGrade rubric, Hemlock Lake pulls an A: clarity at 49.2 ft and phosphorus readings still being added put it in the top bracket for Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI value of 21 puts Hemlock Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake bottoms out at 25 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Hemlock Lake is small — 38 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Hemlock Lake ranks 59 of 140 in Oneida County — solidly in the upper half of the local distribution.

Hemlock Lake has no invasive species recorded in Wisconsin state databases as of 2025, though prevention practices still apply at all access points. The fishery includes walleye alongside the lake's other 3 documented species — a notable draw for Wisconsin anglers. Public access is available — the lake is on the Wisconsin DNR public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-06-11. 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 49.2 ft down. Trophic State Index: 21.

MetricValueGrade
Water Clarity (Secchi Depth)49.2 ftA
PhosphorusNo data
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)21Oligotrophic

Low nutrients, clear water, excellent for swimming

Lake Details

CharacteristicValue
Maximum Depth25 ft
Surface Area38 acres
Public AccessYes

Fish Species

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

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

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

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

Water Quality Trend: Stable

Based on 3 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Stable-0.105 m/yr3
See year-by-year chart →

Recreation & Access

1
Boat Landings
Yes
Public Access

Location

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County Ranking

Ranked #59 of 140 lakes in Oneida County

Nearby Lakes in Oneida County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. 1 station on file (most recent sample 2025).

Fish Species (DNR-rated)

Panfish(Common)Largemouth Bass(Common)Walleye(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: 2025-06-11

Monitoring stations: 1