Portage Lake
Portage Lake in Hubbard County, Minnesota has a water quality grade of C (Fair). Water clarity: 5.5 ft visibility. Phosphorus: 30.5 µg/L. Chlorophyll-a (algae): 11.2 µg/L. Maximum depth: 17 ft. Surface area: 428.71 acres.
- Clarity
- 5.5 ft
- Typical in August
- 73°F
- Max depth
- 17 ft
- Area
- 429 acres
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Apr 18
- Open water
- 211 days
Next lake in Hubbard County
Portage Lake is a 429-acre productive, nutrient-rich eutrophic lake in Hubbard County, Minnesota with a maximum depth of 17 feet (10-foot average). Water quality is graded C based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 12 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 67 other monitored lakes in Hubbard County, Portage Lake ranks #60 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-06. 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)
Murky, only visible to about 5.5 ft. Phosphorus level: 30.5 µg/L. Chlorophyll-a: 11.2 µg/L. Trophic State Index: 53.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.5 ft | Not graded |
| Phosphorus | 30.5 µg/L | Fair |
| Chlorophyll-a (Algae) | 11.2 µg/L | Fair |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Portage Lake
Compare lakeside cabins, hotels, and vacation rentals near Portage Lake in Hubbard 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 73°F at the surface in August. Summer average is about 72°F. Usually warmest in Jul (about 75°F) and coldest in Oct (about 52°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 475 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 (36,983 cells/mL) on July 4, 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 | 17 ft |
| Average Depth | 10 ft |
| Surface Area | 429 acres |
| Shoreline Length | 5.3 mi |
| Littoral Zone | 96% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Portage LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Portage Lake
DNR Fisheries Survey Summary
13 surveys on file from MN DNR Fisheries. Most recent: 2022-08-08 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 21.92 | 0.38 lb |
| Brown Bullhead | 14.21 | 0.63 lb |
| Bluegill | 11.26 | 0.19 lb |
| Yellow Perch | 7.63 | 0.12 lb |
| Northern Pike | 6.28 | 1.8 lb |
| Black Crappie | 6.06 | 0.34 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
Brown Bullhead
Bluegill
Yellow Perch
From the 2022-08-08 survey
Portage Lake is located three miles northwest of Park Rapids in west-central Hubbard County. Portage has a surface area of 429 acres and a maximum depth of 17 feet. A county owned public access is located on the south shore of the lake. Portage is a very popular lake for ice fishing, as it is one of the first lakes to…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Portage Lake. 4 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
- —Aquatic Plant Report — Portage (1264)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — PortageFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — PortagePublic 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 | -0.179 m/yr | 6 |
| Phosphorus | ↓ Declining | +4.56 µg/L/yr | 6 |
| Chlorophyll-a | ↓ Declining | +0.67 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (159 observations).
Estimated open water season: 211 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-14 (2024) | 2013-05-09 (2013) |
| Ice-In | 1993-10-31 (1993) | 2009-12-05 (2009) |
Most recent ice-out: 2024-03-14
Reservoir Info (USACE NID)
Portage Lake is a man-made reservoir impounded by the Portage Lake (completed 1938), built primarily for recreation on the Portage River; gravity-type dam, 12 ft tall and 11 ft long.
- Surface area
- 422 ac
- Normal storage
- 4,120 ac-ft
- Max storage
- 5,320 ac-ft
- Drainage area
- 4.9 sq mi
- Hazard class
- Low
- Owner
- MNDNR
Source: USACE National Inventory of Dams, NID ID MN00185 · Operator website
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 MN29-0250-00 · Official waterbody report
County Ranking
Ranked #60 of 68 lakes in Hubbard County
Nearby Lakes With Higher Grades
Portage 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 Hubbard County
Frequently asked questions about Portage Lake
What is the water quality grade for Portage Lake?
- Portage Lake in Hubbard County, Minnesota has a water quality grade of C (Fair). Water clarity: 5.5 ft visibility. Phosphorus: 30.5 µg/L. Chlorophyll-a (algae): 11.2 µg/L. Maximum depth: 17 ft. Surface area: 428.71 acres.
Is Portage Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Portage Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 11.2 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Portage Lake?
- Portage Lake typically sits around 73°F at the surface in August, from 475 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 17 feet and an average depth of 10 feet. The lake covers 428.71 acres.
What fish are in Portage Lake?
- Fish species found in Portage Lake include black bullhead, black crappie, bluegill, brown bullhead, largemouth bass, northern pike, pumpkinseed, rock bass, walleye, white sucker, yellow bullhead, yellow perch. Portage Lake is located in Hubbard County, Minnesota.
When does Portage Lake thaw?
- Portage Lake typically has ice-out around Apr 18. Ice typically forms around Nov 15. The open water season is approximately 211 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 (36,983 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 Portage Lake. Public access is listed as yes.
Explore Portage Lake across LakeGrade
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Where this data comes from
271 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
MNPCA271 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- Phosphorus by 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
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