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LakeQuality

North Twin Lake

NR
Not yet rated
14 ft clear · Oligotrophic · 2,871 acres
Limited DataOligotrophic

North Twin Lake in Vilas County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 14 ft visibility. Maximum depth: 60 ft. Surface area: 2871 acres.

Wisconsin DNR lists Musky as common on North Twin Lake. DNR survey details →

Clarity
14 ft
Max depth
60 ft
Area
2,871 acres
Trend
Declining
Public access
Yes

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Why North Twin Lake has no grade

We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For North Twin Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).

Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.

Sampling is run by WI DNR and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.

North Twin Lake is a 2,871-acre lake in Vilas County, Wisconsin with a maximum depth of 60 feet. Overall water quality is declining over recent sampling years. The lake supports 5 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 4 public boat landings.

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

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Swimming Safety

Not rated

Limited data

Not rated for swimming — there is not enough monitoring data to judge this lake

Compare the safest swimming lakes near Eagle River

Get alerts for North Twin Lake

Water quality measurements for North Twin Lake

These readings exist but are not enough for an A–F grade — see why.

Good clarity, visible to about 14 ft. Trophic State Index: 39.

MetricValueGrade
Water Clarity (Secchi Depth)14 ftNot graded
PhosphorusNo recent samples
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)39Oligotrophic

Low nutrients, clear water, excellent for swimming

Where to stay near North Twin Lake

Compare lakeside cabins, hotels, and vacation rentals near North Twin Lake in Vilas County, Wisconsin — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.

Top-rated places to stay near North Twin Lake

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? Cabins and lodging at North Twin Lake · more Wisconsin lake trips

Blue-Green Algae (Cyanobacteria)

No current satellite reading

There’s no recent EPA CyAN cyanobacteria estimate for North Twin Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was low (8,551 cells/mL) on June 27, 2026.

Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗

DNR fisheries survey

Wisconsin DNR lists Musky as common on North Twin Lake.

A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality does not assign an A–F grade on North Twin Lake — official chemistry is on file, not a letter, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1993. 15 stations on file (most recent sample 2025).

DNR Assessment
Reported
Trophic State Index 44 (mesotrophic) · 5-year average

Fish Species (DNR-rated)

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

Lake Details

CharacteristicValue
Maximum Depth60 ft
Surface Area2,871 acres
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
27 sq mi
Shoreline
14 mi
Elevation
1,677 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Recreation & Access

4
Boat Landings
Yes
Public Access
  • North Twin Lake - Millerville LanePublic
  • North Twin Lake - Lakota RoadPublic
  • Manuel LakePublic
  • South Twin Lake - Twin Lake RoadPublic

Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps

Fish Species

Click a species to see every graded lake where it is documented.

Fishing North Twin Lake

Invasive & Introduced Species

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

Chinese Mystery SnailEurasian Water-MilfoilRusty Crayfish

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

MetricTrendChange/YearYears
Water Clarity Declining-0.771 m/yr6
See year-by-year chart →

Regulated Pollution Sources Nearby

1 EPA-permitted facility operate within about 5 miles of North Twin Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.

  • Phelps Sanitary District #1
    Phelps · 2.4 mi away · NPDES WI0029050
    Recent violation

Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.

Graded lakes near North Twin Lake

North Twin Lake has no grade, but these lakes within a short drive do.

Nearby Lakes in Vilas County

Frequently asked questions about North Twin Lake

Where is North Twin Lake?

North Twin Lake is a lake in Vilas County, Wisconsin. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.

What is the water quality grade for North Twin Lake?

North Twin Lake in Vilas County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 14 ft visibility. Maximum depth: 60 ft. Surface area: 2871 acres.

Is North Twin Lake safe to swim in?

Not rated for swimming — there is not enough monitoring data to judge this lake. North Twin Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.

How deep is North Twin Lake?

North Twin Lake has a maximum depth of 60 feet. The lake covers 2871 acres.

What fish are in North Twin Lake?

Fish species found in North Twin Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Walleye. North Twin Lake is located in Vilas County, Wisconsin.

What did the DNR fisheries survey find at North Twin Lake?

Wisconsin DNR lists Musky as common on North Twin Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality does not assign an A–F grade on North Twin Lake — official chemistry is on file, not a letter, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.

Does North Twin Lake have blue-green algae?

There is no recent EPA CyAN cyanobacteria estimate for North Twin Lake (clouds, ice, or an off-season gap). The most recent reading was low (8,551 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.

Are there boat ramps on North Twin Lake?

North Twin Lake has 4 documented boat landings in the USGS National Boat Ramps inventory. Named access points include North Twin Lake - Millerville Lane, North Twin Lake - Lakota Road, Manuel Lake, South Twin Lake - Twin Lake Road. Public access is listed as yes.

Where this data comes from

52 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Wisconsin Department of Natural ResourcesWIDNR_WQX52 samples · 2020–2025
Monitoring station identifiers (2)

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.

Other records on this page

Regulated discharger data from EPA ECHO (ICIS-NPDES)

Lake size & watershed from HydroLAKES (HydroSHEDS)

Fish and recreation data from Wisconsin DNR Lakes

Named boat-access points from the USGS National Boat Ramps inventory