Long Lost Lake
Long Lost Lake in Clearwater County, Minnesota has a water quality grade of A (Excellent). Water clarity: 22 ft visibility. Phosphorus: 10.5 µg/L. Chlorophyll-a (algae): 2.4 µg/L. Maximum depth: 63 ft. Surface area: 539.04 acres.
- Clarity
- 22 ft
- Typical in August
- 75°F
- Max depth
- 63 ft
- Area
- 539 acres
- Type
- Oligotrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Apr 19
- Open water
- 224 days
Next lake in Clearwater County
Long Lost Lake is a 539-acre cold, clear oligotrophic lake in Clearwater County, Minnesota with a maximum depth of 63 feet (13-foot average). Water quality is graded A based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 11 documented fish species including black crappie, bluegill, and brown bullhead. Public access is available with 1 public boat landing. Compared to the 36 other monitored lakes in Clearwater County, Long Lost Lake ranks #15 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-02. 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 22 ft down. Phosphorus level: 10.5 µg/L. Chlorophyll-a: 2.4 µg/L. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 22 ft | Not graded |
| Phosphorus | 10.5 µg/L | Good |
| Chlorophyll-a (Algae) | 2.4 µg/L | Good |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Long Lost Lake
Compare lakeside cabins, hotels, and vacation rentals near Long Lost Lake in Clearwater 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
Long Lost Lake typically sits around 75°F at the surface in August. Summer average is about 69°F. Usually warmest in Aug (about 75°F) and coldest in Jun (about 59°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 84 field readings (2011–2025) via the EPA Water Quality Portal. See the full Long Lost Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 63 ft |
| Average Depth | 12.5 ft |
| Surface Area | 539 acres |
| Shoreline Length | 14.3 mi |
| Littoral Zone | 51% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Long Lost LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Long Lost Lake
DNR Fisheries Survey Summary
8 surveys on file from MN DNR Fisheries. Most recent: 2024-07-29 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluntnose Minnow | 40.40 | — |
| Bluegill | 16.83 | 0.26 lb |
| Largemouth Bass | 9.96 | 0.82 lb |
| JND | 5.18 | — |
| Yellow Perch | 4.54 | 0.2 lb |
| Northern Pike | 4.06 | 1.37 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
Largemouth Bass
Yellow Perch
Northern Pike
From the 2024-07-29 survey
Long Lost Lake is a 501-acre lake with a maximum depth of 63 feet located 8 miles south of the town of Zerkel in southern Clearwater County. Lake levels rose considerably since the early 1990s but have receded several feet in recent years, although the lake is still higher than historic levels. This has resulted in…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Long Lost Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Long LostFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Long Lost (1338)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — Long LostFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Long LostPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.292 m/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (18 observations).
Estimated open water season: 224 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2010-04-02 (2010) | 2013-05-14 (2013) |
| Ice-In | 2003-11-08 (2003) | 2006-11-30 (2006) |
Most recent ice-out: 2020-04-29
EPA Impairment Status
Long Lost 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 MN15-0068-00 · Official waterbody report
County Ranking
Ranked #15 of 37 lakes in Clearwater County
Nearby Lakes in Clearwater County
Frequently asked questions about Long Lost Lake
What is the water quality grade for Long Lost Lake?
- Long Lost Lake in Clearwater County, Minnesota has a water quality grade of A (Excellent). Water clarity: 22 ft visibility. Phosphorus: 10.5 µg/L. Chlorophyll-a (algae): 2.4 µg/L. Maximum depth: 63 ft. Surface area: 539.04 acres.
Is Long Lost Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Long Lost 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 Long Lost Lake?
- Long Lost Lake typically sits around 75°F at the surface in August, from 84 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Long Lost Lake?
- Long Lost Lake has a maximum depth of 63 feet and an average depth of 12.5 feet. The lake covers 539.04 acres.
What fish are in Long Lost Lake?
- Fish species found in Long Lost Lake include black crappie, bluegill, brown bullhead, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, smallmouth bass, walleye, white sucker, yellow perch. Long Lost Lake is located in Clearwater County, Minnesota.
When does Long Lost Lake thaw?
- Long Lost Lake typically has ice-out around Apr 19. Ice typically forms around Nov 29. The open water season is approximately 224 days.
Are there boat ramps on Long Lost Lake?
- Long Lost Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Long Lost Lake. Public access is listed as yes.
Explore Long Lost Lake across LakeGrade
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Where this data comes from
118 measurements from 4 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
MNPCA72 samples · 2020–2025 - Minnesota Chippewa Tribe, Minnesota (White Earth Band) (Tribal)
WEARTH_WQX46 samples · 2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity by Nephelometry
Monitoring station identifiers (4)
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
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate