Long Lake
Long Lake in Becker County, Minnesota has a water quality grade of A (Excellent). Water clarity: 19.5 ft visibility. Phosphorus: 8 µg/L. Chlorophyll-a (algae): 2.7 µg/L. Maximum depth: 61 ft. Surface area: 414.51 acres.
- Clarity
- 19.5 ft
- Typical in August
- 60°F
- Max depth
- 61 ft
- Area
- 415 acres
- Type
- Oligotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 19
- Open water
- 219 days
Next lake in Becker County
Long Lake is a 415-acre cold, clear oligotrophic lake in Becker County, Minnesota with a maximum depth of 61 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 16 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 83 other monitored lakes in Becker County, Long Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-17. 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 19.5 ft down. Phosphorus level: 8 µg/L. Chlorophyll-a: 2.7 µg/L. Trophic State Index: 36.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 19.5 ft | Not graded |
| Phosphorus | 8 µg/L | Good |
| Chlorophyll-a (Algae) | 2.7 µg/L | Good |
| Trophic State Index (TSI) | 36 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Long Lake
Compare lakeside cabins, hotels, and vacation rentals near Long Lake in Becker 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 Lake typically sits around 60°F at the surface in August. Summer average is about 58°F. Usually warmest in Aug (about 60°F) and coldest in May (about 54°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 1,128 field readings (2010–2025) via the EPA Water Quality Portal. See the full Long Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Long Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (87,096 cells/mL) on May 9, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 61 ft |
| Surface Area | 415 acres |
| Shoreline Length | 6.4 mi |
| Littoral Zone | 37% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Airport ParkPublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Long 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
14 surveys on file from MN DNR Fisheries. Most recent: 2021-06-28 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| MMS | 168.13 | — |
| Bluntnose Minnow | 109.02 | — |
| BKF | 65.54 | — |
| Bluegill | 25.98 | 0.17 lb |
| BCS | 8.50 | — |
| Northern Pike | 8.25 | 1.33 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
Northern Pike
From the 2021-06-28 survey
Long Lake is a 415-acre lake located in Becker County on the western city limits of Detroit Lakes. Long Lake possesses a heavily developed shoreline and receives a high level of recreational use and angling pressure, particularly during the open water season. Zebra mussels were discovered in the lake in 2020. A…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Long Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — LongFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — LongFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — LongPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.121 m/yr | 6 |
| Phosphorus | ↑ Improving | -4.44 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.78 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (145 observations).
Estimated open water season: 219 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-21 (2024) | 2013-05-11 (2013) |
| Ice-In | 1991-11-04 (1991) | 2004-12-14 (2004) |
Most recent ice-out: 2025-04-14
Reservoir Info (USACE NID)
Long Lake is a man-made reservoir impounded by the Long Lake (completed 1936), built primarily for recreation on the Pelican River-TR; gravity-type dam, 9 ft tall.
- Surface area
- 45 ac
- Normal storage
- 4,365 ac-ft
- Max storage
- 5,335 ac-ft
- Drainage area
- 3.2 sq mi
- Hazard class
- Low
- Owner
- MNDNR
Source: USACE National Inventory of Dams, NID ID MN00882 · Operator website
EPA Impairment Status
Long 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 MN03-0383-00 · Official waterbody report
County Ranking
Ranked #5 of 84 lakes in Becker County
Nearby Lakes in Becker County
Frequently asked questions about Long Lake
What is the water quality grade for Long Lake?
- Long Lake in Becker County, Minnesota has a water quality grade of A (Excellent). Water clarity: 19.5 ft visibility. Phosphorus: 8 µg/L. Chlorophyll-a (algae): 2.7 µg/L. Maximum depth: 61 ft. Surface area: 414.51 acres.
Is Long Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Long Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.7 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Long Lake?
- Long Lake typically sits around 60°F at the surface in August, from 1,128 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Long Lake?
- Long Lake has a maximum depth of 61 feet. The lake covers 414.51 acres.
What fish are in Long Lake?
- Fish species found in Long Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Long Lake is located in Becker County, Minnesota.
When does Long Lake thaw?
- Long Lake typically has ice-out around Apr 19. Ice typically forms around Nov 24. The open water season is approximately 219 days.
Does Long Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Long Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (87,096 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Long Lake?
- Long Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Airport Park. Public access is listed as yes.
Explore Long Lake across LakeGrade
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Where this data comes from
189 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
MNPCA189 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
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