Johnson Lake
Johnson Lake in Clearwater County, Minnesota has a water quality grade of C (Fair). Water clarity: 7.7 ft visibility. Phosphorus: 26 µg/L. Chlorophyll-a (algae): 7.6 µg/L. Maximum depth: 70 ft. Surface area: 63.04 acres.
- Clarity
- 7.7 ft
- Typical in August
- 52°F
- Max depth
- 70 ft
- Area
- 63 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
Next lake in Clearwater County
Johnson Lake is a 63-acre mesotrophic lake in Clearwater County, Minnesota with a maximum depth of 70 feet. Water quality is graded C based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 9 documented fish species including black bullhead, bluegill, and brown bullhead. Public access is available with 1 public boat landing. Compared to the 36 other monitored lakes in Clearwater County, Johnson Lake ranks #29 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-10. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyModerate
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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Moderate clarity, visible to about 7.7 ft. Phosphorus level: 26 µg/L. Chlorophyll-a: 7.6 µg/L. Trophic State Index: 50.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.7 ft | Not graded |
| Phosphorus | 26 µg/L | Fair |
| Chlorophyll-a (Algae) | 7.6 µg/L | Fair |
| Trophic State Index (TSI) | 50 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Johnson Lake
Compare lakeside cabins, hotels, and vacation rentals near Johnson 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
Johnson Lake typically sits around 52°F at the surface in August. Summer average is about 51°F. Usually warmest in Jul (about 52°F) and coldest in May (about 48°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 561 field readings (2011–2025) via the EPA Water Quality Portal. See the full Johnson Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 70 ft |
| Surface Area | 63 acres |
| Shoreline Length | 2.1 mi |
| Littoral Zone | 25% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Johnson LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Johnson Lake
DNR Fisheries Survey Summary
8 surveys on file from MN DNR Fisheries. Most recent: 2023-06-12 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 40.94 | 0.12 lb |
| Yellow Perch | 39.11 | 0.18 lb |
| Pumpkinseed | 6.48 | 0.07 lb |
| CNM | 4.31 | — |
| CRC | 4.31 | — |
| Northern Pike | 3.85 | 1.66 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
Yellow Perch
Pumpkinseed
Northern Pike
From the 2023-06-12 survey
Johnson Lake (also known as Grant Lake) is a 63-acre, undeveloped natural lake located 8 miles northeast of Clearbrook in northern Clearwater County. Johnson has an average water clarity of 7 feet and a maximum depth of 70 feet. Johnson Lake has multiple small inlets and one outlet connecting to the Clearwater River.…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Johnson Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — JohnsonFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Johnson (1704)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — JohnsonFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — JohnsonPublic 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 | +0.095 m/yr | 6 |
| Phosphorus | ↑ Improving | -1.11 µg/L/yr | 6 |
| Chlorophyll-a | ↓ Declining | +0.42 µg/L/yr | 6 |
County Ranking
Ranked #29 of 37 lakes in Clearwater County
Nearby Lakes With Higher Grades
Johnson Lake holds Grade C. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Clearwater County
Frequently asked questions about Johnson Lake
What is the water quality grade for Johnson Lake?
- Johnson Lake in Clearwater County, Minnesota has a water quality grade of C (Fair). Water clarity: 7.7 ft visibility. Phosphorus: 26 µg/L. Chlorophyll-a (algae): 7.6 µg/L. Maximum depth: 70 ft. Surface area: 63.04 acres.
Is Johnson Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Johnson Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 7.6 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Johnson Lake?
- Johnson Lake typically sits around 52°F at the surface in August, from 561 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Johnson Lake?
- Johnson Lake has a maximum depth of 70 feet. The lake covers 63.04 acres.
What fish are in Johnson Lake?
- Fish species found in Johnson Lake include black bullhead, bluegill, brown bullhead, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow perch. Johnson Lake is located in Clearwater County, Minnesota.
Are there boat ramps on Johnson Lake?
- Johnson Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Johnson Lake. Public access is listed as yes.
Explore Johnson Lake across LakeGrade
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Where this data comes from
90 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA90 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 (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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory