Johnson Lake
Johnson Lake in Itasca County, Minnesota has a water quality grade of A (Excellent). Water clarity: 15.7 ft visibility. Phosphorus: 9.5 µg/L. Chlorophyll-a (algae): 2.7 µg/L. Maximum depth: 88 ft. Surface area: 434.03 acres.
- Clarity
- 15.7 ft
- Typical in August
- 74°F
- Max depth
- 88 ft
- Area
- 434 acres
- Type
- Oligotrophic
- Trend
- → Stable
- Public access
- Yes
- Ice-out
- Apr 22
- Open water
- 217 days
Next lake in Itasca County
Johnson Lake is a 434-acre cold, clear oligotrophic lake in Itasca County, Minnesota with a maximum depth of 88 feet. Water quality is graded A based on 2 sampling years through 2025. Phosphorus level is declining over recent sampling years. The lake supports 11 documented fish species including black crappie, bluegill, and hybrid sunfish. Public access is available with 1 public boat landing. Compared to the 71 other monitored lakes in Itasca County, Johnson Lake ranks #31 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-17. Grade methodology: LakeGrade methodology.
Watch Johnson Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
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 15.7 ft down. Phosphorus level: 9.5 µg/L. Chlorophyll-a: 2.7 µg/L. Trophic State Index: 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 15.7 ft | Not graded |
| Phosphorus | 9.5 µg/L | Good |
| Chlorophyll-a (Algae) | 2.7 µg/L | Good |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Johnson Lake
Compare lakeside cabins, hotels, and vacation rentals near Johnson Lake in Itasca 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 Johnson Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Johnson Lake typically sits around 74°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 75°F) and coldest in Sep (about 67°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 19 field readings (2010–2021) via the EPA Water Quality Portal. See the full Johnson Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 88 ft |
| Surface Area | 434 acres |
| Shoreline Length | 7.4 mi |
| Littoral Zone | 34% |
| 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
13 surveys on file from MN DNR Fisheries. Most recent: 2025-06-18 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| CNM | 13.67 | — |
| Bluegill | 8.35 | 0.13 lb |
| Northern Pike | 3.97 | 2 lb |
| Yellow Perch | 3.95 | 0.15 lb |
| Bluntnose Minnow | 3.36 | — |
| Largemouth Bass | 3.15 | 0.72 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
Yellow Perch
Largemouth Bass
From the 2025-06-18 survey
Johnson Lake is a clear, deep lake covering about 492 acres and located roughly thirteen miles north of Grand Rapids, Minnesota. The lake reaches a maximum depth of 88 feet and has excellent water clarity, with visibility of about 17 feet during the 2025 survey. Shallow nearshore habitat makes up about 146 acres, and…
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 (0614)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: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.02 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.91 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.11 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (57 observations).
Estimated open water season: 217 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 1987-04-09 (1987) | 1996-05-08 (1996) |
| Ice-In | 1998-11-12 (1998) | 1989-12-21 (1989) |
Most recent ice-out: 2008-05-06
County Ranking
Ranked #31 of 72 lakes in Itasca County
Nearby Lakes in Itasca County
Frequently asked questions about Johnson Lake
What is the water quality grade for Johnson Lake?
- Johnson Lake in Itasca County, Minnesota has a water quality grade of A (Excellent). Water clarity: 15.7 ft visibility. Phosphorus: 9.5 µg/L. Chlorophyll-a (algae): 2.7 µg/L. Maximum depth: 88 ft. Surface area: 434.03 acres.
Is Johnson Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Johnson 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 Johnson Lake?
- Johnson Lake typically sits around 74°F at the surface in August, from 19 EPA Water Quality Portal field readings (2010–2021). That is a typical value for the month, not a live reading.
How deep is Johnson Lake?
- Johnson Lake has a maximum depth of 88 feet. The lake covers 434.03 acres.
What fish are in Johnson Lake?
- Fish species found in Johnson Lake include black crappie, bluegill, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white sucker, yellow perch. Johnson Lake is located in Itasca County, Minnesota.
When does Johnson Lake thaw?
- Johnson Lake typically has ice-out around Apr 22. Ice typically forms around Nov 25. The open water season is approximately 217 days.
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
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Itasca County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Mississippi Headwaters, ranked by water quality
Lakes in the Rainy Lake Watershed, ranked by water quality
Low nutrients, clear water, excellent for swimming
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Johnson Lake
Other Grade A Lakes in Minnesota
Oligotrophic Lakes in Minnesota
Compare Johnson Lake With Nearby Lakes
Where this data comes from
57 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
MNPCA57 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
Ice data from Minnesota DNR Climate