Ponto Lake
Ponto Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Water clarity: 19 ft visibility. Phosphorus: 8 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Maximum depth: 60 ft. Surface area: 388.05 acres.
- Clarity
- 19 ft
- Typical in August
- 75°F
- Max depth
- 60 ft
- Area
- 388 acres
- Type
- Oligotrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Apr 20
- Open water
- 219 days
Next lake in Cass County
Ponto Lake is a 388-acre cold, clear oligotrophic lake in Cass County, Minnesota with a maximum depth of 60 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is declining 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 103 other monitored lakes in Cass County, Ponto Lake ranks #42 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-29. 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 ft down. Phosphorus level: 8 µg/L. Chlorophyll-a: 2.1 µg/L. Trophic State Index: 36.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 19 ft | Not graded |
| Phosphorus | 8 µg/L | Good |
| Chlorophyll-a (Algae) | 2.1 µg/L | Good |
| Trophic State Index (TSI) | 36 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Ponto Lake
Compare lakeside cabins, hotels, and vacation rentals near Ponto Lake in Cass 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
Ponto Lake typically sits around 75°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 76°F) and coldest in May (about 56°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 30 field readings (2011–2024) via the EPA Water Quality Portal. See the full Ponto Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 60 ft |
| Surface Area | 388 acres |
| Shoreline Length | 4.5 mi |
| Littoral Zone | 26% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Ponto LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Ponto Lake
DNR Fisheries Survey Summary
12 surveys on file from MN DNR Fisheries. Most recent: 2024-08-19 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluntnose Minnow | 56.08 | — |
| Bluegill | 18.16 | 0.13 lb |
| Yellow Perch | 6.93 | 0.15 lb |
| Largemouth Bass | 5.49 | 0.73 lb |
| Northern Pike | 5.10 | 1.65 lb |
| Walleye | 4.29 | 2.08 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.
Bluntnose Minnow
Bluegill
Yellow Perch
Largemouth Bass
From the 2024-08-19 survey
Ponto Lake is a 388-acre lake located northeast of Backus, Minnesota. A DNR owned public access is located on the southeast shore. Ponto Lake has 4.53 miles of shoreline, 102 littoral acres and a maximum depth of 60 feet. The Minnesota Department of Natural Resources (MNDNR) has classified Minnesota's lakes into 43…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Ponto Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — PontoFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Ponto (1543)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — PontoFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — PontoPublic 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 | → Stable | +0.039 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.88 µg/L/yr | 3 |
| Chlorophyll-a | ↓ Declining | +0.14 µg/L/yr | 3 |
Ice Season
Historical ice data from Minnesota DNR (57 observations).
Estimated open water season: 219 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2021-04-05 (2021) | 2013-05-13 (2013) |
| Ice-In | 1995-11-11 (1995) | 2001-12-20 (2001) |
Most recent ice-out: 2021-04-05
County Ranking
Ranked #42 of 104 lakes in Cass County
Nearby Lakes in Cass County
Frequently asked questions about Ponto Lake
What is the water quality grade for Ponto Lake?
- Ponto Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Water clarity: 19 ft visibility. Phosphorus: 8 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Maximum depth: 60 ft. Surface area: 388.05 acres.
Is Ponto Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Ponto Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.1 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Ponto Lake?
- Ponto Lake typically sits around 75°F at the surface in August, from 30 EPA Water Quality Portal field readings (2011–2024). That is a typical value for the month, not a live reading.
How deep is Ponto Lake?
- Ponto Lake has a maximum depth of 60 feet. The lake covers 388.05 acres.
What fish are in Ponto Lake?
- Fish species found in Ponto Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, burbot, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. Ponto Lake is located in Cass County, Minnesota.
When does Ponto Lake thaw?
- Ponto Lake typically has ice-out around Apr 20. Ice typically forms around Nov 25. The open water season is approximately 219 days.
Are there boat ramps on Ponto Lake?
- Ponto Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Ponto Lake. Public access is listed as yes.
Explore Ponto 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
Ice data from Minnesota DNR Climate