Little Carnelian Lake
Little Carnelian Lake in Washington County, Minnesota has a water quality grade of A (Excellent). Water clarity: 20 ft visibility. Phosphorus: 9 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Maximum depth: 68 ft. Surface area: 136.62 acres.
- Clarity
- 20 ft
- Typical in August
- 56°F
- Max depth
- 68 ft
- Area
- 137 acres
- Type
- Oligotrophic
- Trend
- ↑ Improving
- Public access
- No
Next lake in Washington County
Little Carnelian Lake is a 137-acre cold, clear oligotrophic lake in Washington County, Minnesota with a maximum depth of 68 feet. Water quality is graded A based on 2 sampling years through 2024. Overall water quality is improving 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 74 other monitored lakes in Washington County, Little Carnelian Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-17. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited data
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 20 ft down. Phosphorus level: 9 µg/L. Chlorophyll-a: 2.1 µg/L. Trophic State Index: 36.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 20 ft | Not graded |
| Phosphorus | 9 µg/L | Good |
| Chlorophyll-a (Algae) | 2.1 µg/L | Good |
| Trophic State Index (TSI) | 36 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Little Carnelian Lake
Compare lakeside cabins, hotels, and vacation rentals near Little Carnelian Lake in Washington 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.
Top-rated places to stay near Little Carnelian Lake
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Water Temperature
Little Carnelian Lake typically sits around 56°F at the surface in August. Summer average is about 55°F. Usually warmest in Jul (about 56°F) and coldest in Apr (about 43°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 308 field readings (2010–2024) via the EPA Water Quality Portal. See the full Little Carnelian Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 68 ft |
| Surface Area | 137 acres |
| Shoreline Length | 2.6 mi |
| Littoral Zone | 29% |
| Public Access | No |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Little Carnelian 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: 1997-07-14 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 37.52 | 0.11 lb |
| Hybrid Sunfish | 7.40 | 0.17 lb |
| Northern Pike | 4.30 | 1.82 lb |
| Green Sunfish | 3.67 | 0.04 lb |
| Yellow Bass | 2.89 | 0.68 lb |
| Pumpkinseed | 2.48 | 0.18 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.
Bluegill
Hybrid Sunfish
Northern Pike
Green Sunfish
From the 1997-07-14 survey
There is no public access on Little Carnelian Lake so fishing opportunity is limited. Therefore, no stocking is conducted by DNR. The lack of public access also limits angling to riparian owners and their guests.Bluegill are the most abundant species. The 1997 netting shows a dramatic increase in the bluegill…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Little Carnelian Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Little CarnelianFisheries Lake Survey · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.137 m/yr | 5 |
EPA Impairment Status
Little Carnelian Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN82-0014-00 · Official waterbody report
County Ranking
Ranked #9 of 75 lakes in Washington County
Nearby Lakes in Washington County
Frequently asked questions about Little Carnelian Lake
What is the water quality grade for Little Carnelian Lake?
- Little Carnelian Lake in Washington County, Minnesota has a water quality grade of A (Excellent). Water clarity: 20 ft visibility. Phosphorus: 9 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Maximum depth: 68 ft. Surface area: 136.62 acres.
Is Little Carnelian Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Little Carnelian Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.1 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Little Carnelian Lake?
- Little Carnelian Lake typically sits around 56°F at the surface in August, from 308 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
How deep is Little Carnelian Lake?
- Little Carnelian Lake has a maximum depth of 68 feet. The lake covers 136.62 acres.
What fish are in Little Carnelian Lake?
- Fish species found in Little Carnelian Lake include black bullhead, black crappie, bluegill, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, yellow bullhead, yellow perch. Little Carnelian Lake is located in Washington County, Minnesota.
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Where this data comes from
60 measurements from 1 monitoring station, 2021–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA60 samples · 2021–2024
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Analysis of Chlorophyll in Periphyton and Plankton
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)
Lake details from Minnesota DNR LakeFinder