Franklin Lake
Forest County, Wisconsin839 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Franklin Lake. Here is what has been measured.
- Oligotrophic
- Rusty Crayfish
- 46 ft max depth
- Public access
Franklin Lake in Forest County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 16 ft visibility. Phosphorus: 11.3 µg/L. Maximum depth: 46 ft. Surface area: 839 acres.
Wisconsin DNR lists Panfish as common on Franklin Lake. DNR survey details →
Franklin Lake is a 839-acre cold, clear oligotrophic lake in Forest County, Wisconsin with a maximum depth of 46 feet. Overall water quality is declining over recent sampling years. The lake supports 5 documented fish species including Panfish, Largemouth Bass, and Smallmouth Bass. Public access is available with 1 public boat landing. Compared to the 22 other monitored lakes in Forest County, Franklin Lake ranks #14 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-05-07. Methodology: how these readings are compared.
What Franklin Lake is good for
From access and monitoring records, not editorial picks.
- Clear water16 ft of visibility
- Boat launch1 documented ramp
- Fishing5 species recorded
- Camping1 public campground nearby
- Deep water46 ft surveyed max depth
Swimming conditions
Readings onlyLow algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Franklin Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Franklin Lake
These are the measurements Wisconsin DNR publishes for Franklin Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 16 ft down. Phosphorus 11.3 µg/L. TSI 38.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 16ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 11.3µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 38 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Franklin Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Franklin Lake typically sits around 74°F at the surface in August. Summer average is about 71°F. Usually warmest in Jul (about 74°F) and coldest in May (about 55°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (55°F) to its warmest (74°F).
Typical surface water temperature by month, from 14 field readings (2024–2025) via the EPA Water Quality Portal. See the full Franklin Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Franklin Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (48,753 cells/mL) on July 6, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Wisconsin DNR lists Panfish as common on Franklin Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Franklin Lake’s water-quality measurements separately, 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 1986. 2 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Franklin 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).
- 2025Franklin Lake comprehensive survey, 2025Comprehensive Survey · WI DNR · 2025 (PDF)
Lake Details
Max depth
46 ft
Surface area
839 acres
Public access
Yes
Listed by Wisconsin DNR
Recreation & Access
- Franklin LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Franklin Lake
- Franklin Lake0.8 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Stays via Stay22
Stays near Franklin Lake
Compare lakeside cabins, hotels, and vacation rentals near Franklin 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 Franklin Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
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Fish Species
Click a species to see every lake where it is documented.
Fishing Franklin 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.
Water Quality Trend: Worsening
Based on 6 years of monitoring (2020–2025).
Water clarity
Stable6 years
Phosphorus
Worsening+2.53 µg/L/yr6 years
Nearby Lakes in Forest County
Frequently asked questions about Franklin Lake
Where is Franklin Lake?
- Franklin Lake is a lake in Forest County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Franklin Lake?
- Franklin Lake in Forest County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 16 ft visibility. Phosphorus: 11.3 µg/L. Maximum depth: 46 ft. Surface area: 839 acres.
Is Franklin Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Franklin Lake?
- Franklin Lake typically sits around 74°F at the surface in August, from 14 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Franklin Lake?
- Franklin Lake has a maximum depth of 46 feet. The lake covers 839 acres.
What fish are in Franklin Lake?
- Fish species found in Franklin Lake include Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Franklin Lake is located in Forest County, Wisconsin.
What did the DNR fisheries survey find at Franklin Lake?
- Wisconsin DNR lists Panfish as common on Franklin Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Franklin Lake’s water-quality measurements separately, 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 Franklin Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Franklin Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (48,753 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Are there boat ramps on Franklin Lake?
- Franklin Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Franklin Lake. Public access is listed as yes.
Can I fish at Franklin Lake?
- Franklin Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
Are there campgrounds on Franklin Lake?
- Franklin Lake has 1 public campground from USGS The National Map within 5 km, including Franklin Lake. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Franklin Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Wisconsin
Fish species and best lakes in Forest County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Northwoods Wisconsin area
Where to stay at Wisconsin's top lakes, each with its readings
Lakes in the Wolf River Watershed, ranked by water quality
Wisconsin's cleanest lakes, ranked on agency measurements
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Other Lakes in Wisconsin
Oligotrophic Lakes in Wisconsin
Compare Franklin Lake With Nearby Lakes
Where this data comes from
63 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 Resources
WIDNR_WQX63 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles