Portage Lake
Portage Lake in Crow Wing County, Minnesota has a water quality grade of A (Excellent). Water clarity: 11.5 ft visibility. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 3.9 µg/L. Maximum depth: 37 ft. Surface area: 286.83 acres.
- Clarity
- 11.5 ft
- Typical in August
- 74°F
- Max depth
- 37 ft
- Area
- 287 acres
- Type
- Mesotrophic
- Trend
- → Stable
- Public access
- Yes
- Ice-out
- Apr 16
- Open water
- 228 days
Next lake in Crow Wing County
Portage Lake is a 287-acre mesotrophic lake in Crow Wing County, Minnesota with a maximum depth of 37 feet. Water quality is graded A based on 2 sampling years through 2025. Phosphorus level is declining over recent sampling years. The lake supports 15 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 84 other monitored lakes in Crow Wing County, Portage Lake ranks #20 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-14. 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)
Good clarity, visible to about 11.5 ft. Phosphorus level: 13 µg/L. Chlorophyll-a: 3.9 µg/L. Trophic State Index: 42.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 11.5 ft | Not graded |
| Phosphorus | 13 µg/L | Good |
| Chlorophyll-a (Algae) | 3.9 µg/L | Good |
| Trophic State Index (TSI) | 42 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Portage Lake
Compare lakeside cabins, hotels, and vacation rentals near Portage Lake in Crow Wing 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
Portage Lake typically sits around 74°F at the surface in August. Summer average is about 72°F. Usually warmest in Jul (about 76°F) and coldest in May (about 61°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 89 field readings (2010–2025) via the EPA Water Quality Portal. See the full Portage Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Portage Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (38,019 cells/mL) on May 16, 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 | 37 ft |
| Surface Area | 287 acres |
| Shoreline Length | 2.6 mi |
| Littoral Zone | 38% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Crooked LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Portage 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
13 surveys on file from MN DNR Fisheries. Most recent: 2025-06-16 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| GOS | 46.85 | — |
| Bluntnose Minnow | 26.10 | — |
| Bluegill | 26.06 | 0.2 lb |
| Largemouth Bass | 18.73 | 1.26 lb |
| JND | 16.35 | — |
| Yellow Perch | 11.59 | 0.16 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
From the 2025-06-16 survey
A targeted survey of nearshore fish species in Portage Lake was conducted on June 16, 2025, by Lake Biological Monitoring and Assessment (LBMA) Program staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where possible.…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Portage Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — PortageFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — PortageFish Stocking History · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.056 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.36 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.1 µg/L/yr | 5 |
Ice Season
Historical ice data from Minnesota DNR (34 observations).
Estimated open water season: 228 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-03-24 (2012) | 2013-05-10 (2013) |
| Ice-In | 2013-11-24 (2013) | 2015-12-19 (2015) |
Most recent ice-out: 2022-05-03
EPA Impairment Status
Portage 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 MN18-0050-00 · Official waterbody report
County Ranking
Ranked #20 of 85 lakes in Crow Wing County
Nearby Lakes in Crow Wing County
Frequently asked questions about Portage Lake
What is the water quality grade for Portage Lake?
- Portage Lake in Crow Wing County, Minnesota has a water quality grade of A (Excellent). Water clarity: 11.5 ft visibility. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 3.9 µg/L. Maximum depth: 37 ft. Surface area: 286.83 acres.
Is Portage Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Portage Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 3.9 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Portage Lake?
- Portage Lake typically sits around 74°F at the surface in August, from 89 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Portage Lake?
- Portage Lake has a maximum depth of 37 feet. The lake covers 286.83 acres.
What fish are in Portage Lake?
- Fish species found in Portage Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, tullibee (cisco), walleye, yellow bullhead, yellow perch. Portage Lake is located in Crow Wing County, Minnesota.
When does Portage Lake thaw?
- Portage Lake typically has ice-out around Apr 16. Ice typically forms around Nov 30. The open water season is approximately 228 days.
Does Portage Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Portage Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (38,019 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Portage Lake?
- Portage Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Crooked Lake. Public access is listed as yes.
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Where this data comes from
121 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
MNPCA121 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
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
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate