Swift Lake
Cass County, Minnesota357 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Swift Lake. Here is what has been measured.
- Mesotrophic
- 52 ft max depth
- Limited data
Swift Lake in Cass County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 8.5 ft visibility. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 4.9 µg/L. Maximum depth: 52 ft. Surface area: 356.59 acres.
Minnesota DNR's Standard Survey on June 9, 2025 caught 0.44 walleye per gill net at Swift Lake. DNR survey details →
Swift Lake is a 357-acre mesotrophic lake in Cass County, Minnesota with a maximum depth of 52 feet (14-foot average). Overall water quality is improving over recent sampling years. The lake supports 13 documented fish species including black crappie, bluegill, and bowfin (dogfish). No public access — the lake is private or restricted. Compared to the 103 other monitored lakes in Cass County, Swift Lake ranks #63 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-08-29. Methodology: how these readings are compared.
What Swift Lake is good for
From access and monitoring records, not editorial picks.
- Fishing13 species recorded
- Deep water52 ft surveyed max depth
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Swift Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Swift Lake
These are the measurements Minnesota PCA publishes for Swift Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 8.5 ft. Phosphorus 13 µg/L. Chlorophyll-a 4.9 µg/L. TSI 45.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 8.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 13µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 4.9µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 45 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Swift Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Swift Lake typically sits around 51°F at the surface in October. Summer average is about 65°F. Usually warmest in Jul (about 66°F) and coldest in May (about 51°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (51°F) to its warmest (66°F).
Typical surface water temperature by month, from 534 field readings (2011–2025) via the EPA Water Quality Portal. See the full Swift Lake water temperature breakdown →
Minnesota DNR's Standard Survey on June 9, 2025 caught 0.44 walleye per gill net at Swift Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Swift Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
5 surveys on file from MN DNR Fisheries. Most recent: 2025-06-09 (Standard Survey).
5 surveys on file · most recent 2025-06-09 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Yellow Perch | 3.59 | 5–10 in 2025-06-09 | 0.16 lb |
| Bluegill | 2.85 | 2–9 in 2025-06-09 | 0.33 lb |
| Northern Pike | 2.56 | 15–35 in 2025-06-09 | 1.65 lb |
| Black Bullhead | 2.13 | 9–11 in 2002-08-26 | 0.73 lb |
| Tullibee (Cisco) | 1.85 | 14–16 in 2002-08-26 | 1.93 lb |
| Pumpkinseed | 1.71 | 3–7 in 2025-06-09 | 0.29 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
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.
Yellow Perch
Bluegill
Northern Pike
Black Bullhead
From the 2025-06-09 survey
Swift Lake is a 357-acre lake with 6 miles of shoreline and a maximum depth of 52 feet located north of Longville, MN. The DNR has classified Minnesota's lakes into 43 different classes based on physical, chemical and other characteristics. Swift Lake is in Lake Class 25; lakes in this class are generally deep, clear…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Swift Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — SwiftFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Swift (1651)Aquatic Plant Report · MN DNR LakeFinder
Lake Details
Max depth
52 ft
Average depth
14 ft
Surface area
357 acres
Shoreline
5.6 mi
Littoral zone
52%
Share shallower than 15 ft
Public access
No
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
29 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,289 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Swift Lake
Compare lakeside cabins, hotels, and vacation rentals near Swift 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.
Top-rated places to stay near Swift Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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 →
Follow Swift Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fish Species
Click a species to see every lake where it is documented.
Fishing Swift Lake
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Improving-1.07 µg/L/yr6 years
Chlorophyll-a
Improving-1.33 µg/L/yr6 years
Nearby Lakes in Cass County
Frequently asked questions about Swift Lake
Where is Swift Lake?
- Swift Lake is a lake in Cass County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Swift Lake?
- Swift Lake in Cass County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 8.5 ft visibility. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 4.9 µg/L. Maximum depth: 52 ft. Surface area: 356.59 acres.
Is Swift Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Swift Lake?
- Swift Lake typically sits around 51°F at the surface in October, from 534 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Swift Lake?
- Swift Lake has a maximum depth of 52 feet and an average depth of 14 feet. The lake covers 356.59 acres.
What fish are in Swift Lake?
- Fish species found in Swift Lake include black crappie, bluegill, bowfin (dogfish), brown bullhead, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, walleye, white sucker, yellow bullhead, yellow perch. Swift Lake is located in Cass County, Minnesota.
What did the DNR fisheries survey find at Swift Lake?
- Minnesota DNR's Standard Survey on June 9, 2025 caught 0.44 walleye per gill net at Swift Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Swift Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Swift Lake?
- Public access to Swift Lake is listed as no on the lake record, so confirm before you make the trip. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore Swift Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Cass County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Brainerd Lakes area
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the Mississippi Headwaters, ranked by water quality
Lakes in the Pine River Watersheds (Brainerd Lakes), ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
More lakes in Minnesota
State Parks Near Swift Lake
Other Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Where this data comes from
78 measurements from 2 monitoring stations, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Leech Lake Band of Ojibwe
LEECHLAK_WQX70 samples · 2021 - Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA8 samples · 2024–2025
Analytical methods
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Standard Test Method for Sulfate Ion in Water
- Field measurement/observation, generic method
Monitoring station identifiers (2)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder