Courthouse Lake
Courthouse Lake in Carver County, Minnesota has a water quality grade of A (Excellent). Water clarity: 18.9 ft visibility. Phosphorus: 14 µg/L. Chlorophyll-a (algae): 2.4 µg/L. Maximum depth: 57 ft. Surface area: 12.02 acres.
- Clarity
- 18.9 ft
- Typical in August
- 60°F
- Max depth
- 57 ft
- Area
- 12 acres
- Type
- Oligotrophic
- Trend
- ↓ Declining
- Public access
- No
Next lake in Carver County
Courthouse Lake is a 12-acre cold, clear oligotrophic lake in Carver County, Minnesota with a maximum depth of 57 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 10 documented fish species including black bullhead, black crappie, and bluegill. No public access — the lake is private or restricted. Compared to the 37 other monitored lakes in Carver County, Courthouse Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-06. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Crystal clear, you can see 18.9 ft down. Phosphorus level: 14 µg/L. Chlorophyll-a: 2.4 µg/L. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 18.9 ft | Not graded |
| Phosphorus | 14 µg/L | Good |
| Chlorophyll-a (Algae) | 2.4 µg/L | Good |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Courthouse Lake
Compare lakeside cabins, hotels, and vacation rentals near Courthouse Lake in Carver County, Minnesota — 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.
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Water Temperature
Courthouse Lake typically sits around 60°F at the surface in August. Summer average is about 56°F. Usually warmest in Sep (about 63°F) and coldest in Jan (about 38°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 1,699 field readings (2010–2025) via the EPA Water Quality Portal. See the full Courthouse Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 57 ft |
| Surface Area | 12 acres |
| Shoreline Length | 0.7 mi |
| Littoral Zone | 25% |
| Public Access | No |
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Courthouse 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.
DNR Fisheries Survey Summary
4 surveys on file from MN DNR Fisheries. Most recent: 1994-09-07 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 8.02 | 0.24 lb |
| Green Sunfish | 4.77 | 0.08 lb |
| Northern Pike | 4.50 | 1.35 lb |
| White Crappie | 2.96 | 0.17 lb |
| Black Crappie | 2.28 | 0.29 lb |
| Yellow Bass | 1.63 | 0.39 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Black Bullhead
Northern Pike
White Crappie
Black Crappie
From the 1994-09-07 survey
The Courthouse Lake fish population has changed significantly in recent years due to flooding. The 1993 flood allowed many species found in the Minnesota River to migrate into the lake, including northern pike. Since Courthouse is a designated trout lake, northern pike are not a desirable species to have present.…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Courthouse Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — CourthouseFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — CourthouseFish Stocking History · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.14 m/yr | 6 |
| Phosphorus | ↓ Declining | +1.14 µg/L/yr | 6 |
| Chlorophyll-a | → Stable | +0.01 µg/L/yr | 6 |
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Courthouse Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Gedney, M AChaska · 1.4 mi away · NPDES MN0022446Recent violation
- Anchor Block Co-South PlantShakopee · 2.3 mi away · NPDES MN0069281
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #3 of 38 lakes in Carver County
Nearby Lakes in Carver County
Frequently asked questions about Courthouse Lake
What is the water quality grade for Courthouse Lake?
- Courthouse Lake in Carver County, Minnesota has a water quality grade of A (Excellent). Water clarity: 18.9 ft visibility. Phosphorus: 14 µg/L. Chlorophyll-a (algae): 2.4 µg/L. Maximum depth: 57 ft. Surface area: 12.02 acres.
Is Courthouse Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Courthouse Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.4 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Courthouse Lake?
- Courthouse Lake typically sits around 60°F at the surface in August, from 1,699 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Courthouse Lake?
- Courthouse Lake has a maximum depth of 57 feet. The lake covers 12.02 acres.
What fish are in Courthouse Lake?
- Fish species found in Courthouse Lake include black bullhead, black crappie, bluegill, common carp, green sunfish, northern pike, walleye, white crappie, white sucker, yellow bullhead. Courthouse Lake is located in Carver County, Minnesota.
Explore Courthouse Lake across LakeGrade
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Where this data comes from
196 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA196 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (2)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake details from Minnesota DNR LakeFinder