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LakeQuality

Roberts Lake

B
Grade B — Good
Good · #15 of 23 lakes in the county · 11.7 ft clear · Mesotrophic · 435 acres · from A
Limited DataMesotrophic

Roberts Lake in Forest County, Wisconsin has a water quality grade of B (Good). Water clarity: 11.7 ft visibility. Phosphorus: 11.1 µg/L. Maximum depth: 31 ft. Surface area: 435 acres.

Clarity
11.7 ft
Max depth
31 ft
Area
435 acres
Type
Mesotrophic
Trend
Improving
Public access
Yes

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BWindfall Lake10 ft clear · Forest CountyView →
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Roberts Lake is a 435-acre mesotrophic lake in Forest County, Wisconsin with a maximum depth of 31 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 22 other monitored lakes in Forest County, Roberts Lake ranks #15 for water quality.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-06. Grade methodology: LakeGrade methodology.

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Swimming Safety

Grade only

Limited data

Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.

Good for swimming, clear water with low algae levels

Compare the safest swimming lakes near Rhinelander

Get alerts for Roberts Lake

Water Quality Grade: B (Good)

Good clarity, visible to about 11.7 ft. Phosphorus level: 11.1 µg/L. Trophic State Index: 40.

MetricValueGrade
Water Clarity (Secchi Depth)11.7 ftNot graded
Phosphorus11.1 µg/LGood
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)40Mesotrophic

Moderate nutrients, good water quality

Where to stay near Roberts Lake

Compare lakeside cabins, hotels, and vacation rentals near Roberts Lake in Forest 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 Roberts 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 whole trip? See where to stay at Wisconsin’s top lakes →

Lake Details

CharacteristicValue
Maximum Depth31 ft
Surface Area435 acres
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
8 sq mi
Shoreline
4.8 mi
Elevation
1,585 ft

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

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Roberts LakePublic

Fish Species

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

Fishing Roberts 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.

Banded Mystery SnailChinese Mystery SnailEurasian Water-MilfoilHybrid Eurasian / Northern Water-MilfoilRusty CrayfishZebra Mussel

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1995. 1 station on file (most recent sample 2025).

DNR Assessment
Excellent · Deep Lowland lake
Trophic State Index 41 (mesotrophic) · 5-year average

Fish Species (DNR-rated)

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

DNR Reports & Resources

Wisconsin DNR Fisheries scientists publish multi-year survey reports for Roberts Lake covering fish populations, stocking, water quality, and management. 1 report on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

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

MetricTrendChange/YearYears
Water Clarity Improving+0.578 m/yr5
Phosphorus Improving-0.85 µg/L/yr3
See year-by-year chart →

County Ranking

Ranked #15 of 23 lakes in Forest County

Nearby Lakes in Forest County

Frequently asked questions about Roberts Lake

What is the water quality grade for Roberts Lake?

Roberts Lake in Forest County, Wisconsin has a water quality grade of B (Good). Water clarity: 11.7 ft visibility. Phosphorus: 11.1 µg/L. Maximum depth: 31 ft. Surface area: 435 acres.

Is Roberts Lake safe to swim in?

Good for swimming, clear water with low algae levels. Roberts Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.

How deep is Roberts Lake?

Roberts Lake has a maximum depth of 31 feet. The lake covers 435 acres.

What fish are in Roberts Lake?

Fish species found in Roberts Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Roberts Lake is located in Forest County, Wisconsin.

Are there boat ramps on Roberts Lake?

Roberts Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Roberts Lake. Public access is listed as yes.

Mesotrophic Lakes in Wisconsin

Compare Roberts Lake With Nearby Lakes

Where this data comes from

28 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Wisconsin Department of Natural ResourcesWIDNR_WQX28 samples · 2020–2026

Analytical methods

  • Phosphorus by Colorimetry
Monitoring station identifiers (1)

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

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