Hancock Lake
Hancock Lake in Oneida County, Wisconsin has a water quality grade of C (Fair). Water clarity: 5.4 ft visibility. Phosphorus: 25.4 µg/L. Maximum depth: 22 ft. Surface area: 259 acres.
Wisconsin DNR lists Musky as common on Hancock Lake. DNR survey details →
- Clarity
- 5.4 ft
- Typical in August
- 73°F
- Max depth
- 22 ft
- Area
- 259 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
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Hancock Lake is a 259-acre productive, nutrient-rich eutrophic lake in Oneida County, Wisconsin with a maximum depth of 22 feet. Water quality is graded C based on 1 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 5 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 66 other monitored lakes in Oneida County, Hancock Lake ranks #62 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-06-22. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyModerate
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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Murky, only visible to about 5.4 ft. Phosphorus level: 25.4 µg/L. Trophic State Index: 52.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.4 ft | Not graded |
| Phosphorus | 25.4 µg/L | Fair |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 52 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Hancock Lake
Compare lakeside cabins, hotels, and vacation rentals near Hancock Lake in Oneida 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 Hancock Lake
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Water Temperature
Hancock Lake typically sits around 73°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 75°F) and coldest in May (about 67°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 8 field readings (2024–2024) via the EPA Water Quality Portal. See the full Hancock Lake water temperature breakdown →
Wisconsin DNR lists Musky as common on Hancock Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Hancock Lake C from EPA Water Quality Portal chemistry, and the water-quality trend over 6 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 2005. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 22 ft |
| Surface Area | 259 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Hancock LakePublic
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 Hancock 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: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.086 m/yr | 6 |
| Phosphorus | ↑ Improving | -1.83 µg/L/yr | 6 |
Reservoir Info (USACE NID)
Hancock Lake is a man-made reservoir impounded by the Hancock Lake (completed 1930), built primarily for recreation on the LITTLE RICE CREEK; gravity-type dam, 11 ft tall and 50 ft long.
- Surface area
- 259 ac
- Normal storage
- 1,500 ac-ft
- Max storage
- 2,600 ac-ft
- Drainage area
- 22 sq mi
- Hazard class
- Low
- Owner
- TOWN OF WOODBORO
Source: USACE National Inventory of Dams, NID ID WI00684 · Operator website
EPA Impairment Status
Hancock Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10007295 · Official waterbody report
County Ranking
Ranked #62 of 67 lakes in Oneida County
Nearby Lakes With Higher Grades
Hancock Lake holds Grade C. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Oneida County
Frequently asked questions about Hancock Lake
Where is Hancock Lake?
- Hancock Lake is a lake in Oneida County, Wisconsin. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Hancock Lake?
- Hancock Lake in Oneida County, Wisconsin has a water quality grade of C (Fair). Water clarity: 5.4 ft visibility. Phosphorus: 25.4 µg/L. Maximum depth: 22 ft. Surface area: 259 acres.
Is Hancock Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Hancock Lake has a water quality grade of C (Fair). Always check local health department advisories before swimming.
What is the water temperature of Hancock Lake?
- Hancock Lake typically sits around 73°F at the surface in August, from 8 EPA Water Quality Portal field readings (2024–2024). That is a typical value for the month, not a live reading.
How deep is Hancock Lake?
- Hancock Lake has a maximum depth of 22 feet. The lake covers 259 acres.
What fish are in Hancock Lake?
- Fish species found in Hancock Lake include Musky, Panfish, Largemouth Bass, Northern Pike, Walleye. Hancock Lake is located in Oneida County, Wisconsin.
What did the DNR fisheries survey find at Hancock Lake?
- Wisconsin DNR lists Musky as common on Hancock Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Hancock Lake C from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Hancock Lake?
- Hancock Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Hancock Lake. Public access is listed as yes.
Explore Hancock Lake across LakeQuality
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Where this data comes from
41 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX41 samples · 2020–2025
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
Impairment status from EPA ATTAINS 303(d) database
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