Where is Surprise Lake?

Surprise Lake is a lake in Oconto County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.

How deep is Surprise Lake?

Surprise Lake has a maximum depth of 20 feet. The lake covers 66 acres.

What fish are in Surprise Lake?

Fish species found in Surprise Lake include Panfish, Largemouth Bass, Northern Pike, Walleye. Surprise Lake is located in Oconto County, Wisconsin.

Are there boat ramps on Surprise Lake?

Surprise Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Surprise Lake - North, Surprise Lake - South. Public access is listed as yes.

Can I fish at Surprise Lake?

Surprise Lake has 2 documented boat landings 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.

Surprise Lake

Oconto County, Wisconsin66 acresView map Directions

Wisconsin DNR publishes the water-quality measurements for Surprise Lake. Here is what has been measured.

Clarity

8 ft

Typical for Wisconsin

Secchi · sampled 2024

Phosphorus

13.1 µg/L

Less phosphorus than most

Measured by Wisconsin DNR

Max depth

20 ft

Bathymetric survey

Area

66 acres

Surface area

Type

Mesotrophic

Trophic class

Trend

Stable

7 years of samples

Mesotrophic
Purple Loosestrife
20 ft max depth
Public access
Limited data

See the measurements Directions Where to stay

Surprise Lake in Oconto County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 8 ft visibility. Phosphorus: 13.1 µg/L. Maximum depth: 20 ft. Surface area: 66 acres.

Wisconsin DNR lists Panfish as common on Surprise Lake. DNR survey details →

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Surprise Lake is a 66-acre mesotrophic lake in Oconto County, Wisconsin with a maximum depth of 20 feet. The lake supports 4 documented fish species including Panfish, Largemouth Bass, and Northern Pike. Public access is available with 2 public boat landings. Compared to the 38 other monitored lakes in Oconto County, Surprise Lake ranks #19 for water quality.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-09-05. Methodology: how these readings are compared.

What Surprise Lake is good for

From access and monitoring records, not editorial picks.

Boat launch2 documented ramps
Fishing4 species recorded

Swimming conditions

Readings only

Limited data

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 Surprise 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.

Compare swimming lakes near Rhinelander →

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Water quality measurements for Surprise Lake

These are the measurements Wisconsin DNR publishes for Surprise Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.

Moderate clarity, visible to about 8 ft. Phosphorus 13.1 µg/L. TSI 44.

Water quality readings
Measure	Reading	Where it sits
Water clarity (Secchi depth)	8ft	Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer.
Total phosphorus	13.1µg/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.	44	Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic

Moderate nutrients, good water quality

Ask about Surprise Lake

Answers come straight from the public measurements and survey records on this page.

DNR fisheries survey

Wisconsin DNR lists Panfish as common on Surprise Lake.

A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Surprise Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. 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. 2 stations on file (most recent sample 2024).

DNR Assessment

Good · Deep Seepage lake

Trophic State Index 49 (mesotrophic) · 5-year average

Fish Species (DNR-rated)

Panfish(Common)Largemouth Bass(Common)Northern Pike(Present)Walleye(Present)

Contour map (PDF) →Full WI DNR LakePage →Water quality stations →

DNR Reports & Resources

Wisconsin DNR Fisheries scientists publish multi-year survey reports for Surprise 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).

2016
Surprise Lake comprehensive survey, 2016
Comprehensive Survey · WI DNR · 2016 (PDF)

Lake Details

Max depth

20 ft

Surface area

66 acres

Public access

Yes

Listed by Wisconsin DNR

Lake Size & Watershed

Watershed (drainage) area

4 sq mi

HydroLAKES / HydroSHEDS

Shoreline

1.6 mi

HydroLAKES / HydroSHEDS

Elevation

1,342 ft

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

Recreation & Access

Boat Landings

Yes

Public Access

Surprise Lake - NorthPublic
Surprise Lake - SouthPublic

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

Stays via Stay22

Stays near Surprise Lake

Compare lakeside cabins, hotels, and vacation rentals near Surprise Lake in Oconto 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 Surprise Lake

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Planning a whole trip? See where to stay at Wisconsin’s top lakes →

Follow Surprise Lake’s readings

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Fish Species

Panfish Largemouth Bass Northern Pike Walleye

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

Fishing Surprise 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.

Purple Loosestrife

Water Quality Trend: Stable

Based on 7 years of monitoring (2020–2026).

Water clarity
Stable
7 years
Phosphorus
Stable
-0.18 µg/L/yr7 years

See year-by-year chart →

Nearby Lakes in Oconto County

Little Pickerel Lake11 ft clear · Mesotrophic—View →Smoke Lake7.6 ft clear · Mesotrophic—View →Townsend Flowage LakeMesotrophic—View →Pickerel Lake8 ft clear · Mesotrophic—View →Townsend Flowage—View →Horn Lake8.8 ft clear · Mesotrophic—View →

Frequently asked questions about Surprise Lake

Where is Surprise Lake?: Surprise Lake is a lake in Oconto County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Surprise Lake?: Surprise Lake in Oconto County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 8 ft visibility. Phosphorus: 13.1 µg/L. Maximum depth: 20 ft. Surface area: 66 acres.
Is Surprise Lake safe to swim in?: Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Surprise Lake?: Surprise Lake has a maximum depth of 20 feet. The lake covers 66 acres.
What fish are in Surprise Lake?: Fish species found in Surprise Lake include Panfish, Largemouth Bass, Northern Pike, Walleye. Surprise Lake is located in Oconto County, Wisconsin.
What did the DNR fisheries survey find at Surprise Lake?: Wisconsin DNR lists Panfish as common on Surprise Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Surprise Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Surprise Lake?: Surprise Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Surprise Lake - North, Surprise Lake - South. Public access is listed as yes.
Can I fish at Surprise Lake?: Surprise Lake has 2 documented boat landings 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.

Explore Surprise Lake across LakeQuality

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Official ratings and named-lake measurements

State Parks Near Surprise Lake

Governor Thompson State Park

State Park · 17.6 mi

Other Lakes in Wisconsin

Mary Lake

Langlade County · 7 ft

Windfall Lake

Forest County · 10 ft

Jessie Lake

Langlade County · 6.5 ft

Bear Lake

Forest County · 5.6 ft

Sawyer Lake

Langlade County · 10 ft

Roberts Lake

Forest County · 11.7 ft

Mesotrophic Lakes in Wisconsin

Mary Lake Windfall Lake Jessie Lake Little Long Lake

Where this data comes from

27 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

Wisconsin Department of Natural ResourcesWIDNR_WQX27 samples · 2020–2024

Analytical methods

Phosphorus by Colorimetry

Monitoring station identifiers (1)

WIDNR_WQX-433064

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.