Franklin Lake
Oneida County, Wisconsin159 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Franklin Lake. Here is what has been measured.
- Oligotrophic
- Impaired · Mercury
- 25 ft max depth
Franklin Lake in Oneida County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 16.2 ft visibility. Phosphorus: 12.3 µg/L. Maximum depth: 25 ft. Surface area: 159 acres.
Wisconsin DNR lists Musky as present on Franklin Lake. DNR survey details →
Franklin Lake is a 159-acre cold, clear oligotrophic lake in Oneida County, Wisconsin with a maximum depth of 25 feet. Overall water quality is improving over recent sampling years. The lake supports 5 documented fish species including Musky, Panfish, and Largemouth Bass. Compared to the 66 other monitored lakes in Oneida County, Franklin Lake ranks #18 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-30. Methodology: how these readings are compared.
What Franklin Lake is good for
From access and monitoring records, not editorial picks.
- Clear water16.2 ft of visibility
- Fishing5 species recorded
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. Franklin Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. 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 16.2 ft down. Phosphorus 12.3 µg/L. TSI 39.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 16.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 12.3µg/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. | 39 | 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 55°F at the surface in October. Summer average is about 72°F. Usually warmest in Jul (about 74°F) and coldest in Apr (about 46°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (46°F) to its warmest (74°F).
Typical surface water temperature by month, from 78 field readings (2024–2026) via the EPA Water Quality Portal. See the full Franklin Lake water temperature breakdown →
Wisconsin DNR lists Musky as present 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 7 years of monitoring is improving. 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 2001. 1 station on file (most recent sample 2026).
Fish Species (DNR-rated)
Lake Details
Max depth
25 ft
Surface area
159 acres
Lake Size & Watershed
Watershed (drainage) area
1 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2 mi
HydroLAKES / HydroSHEDS
Elevation
1,568 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Franklin Lake
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Top-rated places to stay near Franklin Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Franklin Lake
Water Quality Trend: Improving
Based on 7 years of monitoring (2020–2026).
Water clarity
Stable5 years
Phosphorus
Improving-0.26 µg/L/yr6 years
EPA Impairment Status
Franklin Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Fish consumption.
Source: EPA ATTAINS assessment unit WI10026427 · Official waterbody report
Nearby Lakes in Oneida County
Frequently asked questions about Franklin Lake
Where is Franklin Lake?
- Franklin Lake is a lake in Oneida 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 Oneida County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 16.2 ft visibility. Phosphorus: 12.3 µg/L. Maximum depth: 25 ft. Surface area: 159 acres.
Is Franklin Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Franklin Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
What is the water temperature of Franklin Lake?
- Franklin Lake typically sits around 55°F at the surface in October, from 78 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Franklin Lake?
- Franklin Lake has a maximum depth of 25 feet. The lake covers 159 acres.
What fish are in Franklin Lake?
- Fish species found in Franklin Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike. Franklin Lake is located in Oneida County, Wisconsin.
What did the DNR fisheries survey find at Franklin Lake?
- Wisconsin DNR lists Musky as present 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 7 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Explore Franklin Lake across LakeQuality
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Where this data comes from
119 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_WQX119 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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes