South Long Lake
Crow Wing County, Minnesota1,309 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for South Long Lake. Here is what has been measured.
- Mesotrophic
- Impaired · Mercury
- zebra mussel
- 47 ft max depth
- Public access
South Long Lake in Crow Wing County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 9 ft visibility. Phosphorus: 24 µg/L. Chlorophyll-a (algae): 8.8 µg/L. Maximum depth: 47 ft. Surface area: 1309.05 acres.
Minnesota DNR's Standard Survey on July 21, 2025 caught 4.83 walleye per gill net at South Long Lake. DNR survey details →
Free interactive depth-contour map of South Long Lake, reaching a maximum surveyed depth of 45 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
South Long Lake is a 1,309-acre mesotrophic lake in Crow Wing County, Minnesota with a maximum depth of 47 feet. Water clarity is improving over recent sampling years. The lake supports 17 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, South Long Lake ranks #75 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-09. Methodology: how these readings are compared.
South Long Lake covers about 1,300 acres in Crow Wing County. It has one public boat landing. The median ice-out date is April 16, which is when the open-water season begins. For a place on the water, look through cabin and lake-house rentals near South Long Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What South Long Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing17 species recorded
- Ice seasonIce-out around Apr 16
- Deep water47 ft surveyed max depth
- Big water1,309 acres
Swimming conditions
Readings onlyModerate algae
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. South Long Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether South Long 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 South Long Lake
These are the measurements Minnesota PCA publishes for South Long 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 9 ft. Phosphorus 24 µg/L. Chlorophyll-a 8.8 µg/L. TSI 49.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 24µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 8.8µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 49 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about South Long Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
South Long Lake typically sits around 71°F at the surface in September. Summer average is about 73°F. Usually warmest in Jul (about 73°F) and coldest in May (about 62°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (62°F) to its warmest (73°F).
Typical surface water temperature by month, from 37 field readings (2022–2025) via the EPA Water Quality Portal. See the full South Long Lake water temperature breakdown →
Minnesota DNR's Standard Survey on July 21, 2025 caught 4.83 walleye per gill net at South Long Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows South Long Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
13 surveys on file from MN DNR Fisheries. Most recent: 2025-07-21 (Standard Survey).
13 surveys on file · most recent 2025-07-21 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluegill | 43.51 | 2–8 in 2025-07-21 | 0.17 lb |
| Largemouth Bass | 22.49 | 2–18 in 2025-07-21 | 1.11 lb |
| Bluntnose Minnow | 17.38 | ||
| Yellow Perch | 8.46 | 4–8 in 2025-07-21 | 0.13 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.
Bluegill
Largemouth Bass
Yellow Perch
From the 2025-07-21 survey
South Long is a 1,309 acre lake 9 miles southeast of the city of Brainerd in Crow Wing County. Walleye is the primary management species, with the lake being stocked every other year (odd years) with 922 pounds of fingerlings. When surplus Walleye fry are available, up to 600,000 may be stocked; this last occurred in…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for South Long Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — South LongFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — South Long (0018)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — South LongFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — South LongPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
47 ft
Surface area
1,309 acres
Shoreline
9.8 mi
Littoral zone
35%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
115 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,178 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- South Long LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near South Long Lake
Compare lakeside cabins, hotels, and vacation rentals near South Long 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.
Top-rated places to stay near South Long 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 South Long 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 South Long 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.
Water Quality Trend: Stable
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Stable-0.24 µg/L/yr6 years
Chlorophyll-a
Worsening+0.24 µg/L/yr6 years
Ice season
Typical ice-out
Apr 16
Earliest Mar 21, 2012 · Latest May 11, 2013
Typical ice-in
Nov 27
Earliest Nov 5, 2011 · Latest Dec 19, 2015
Most recent ice-out
Apr 8
2014
32 observations · Minnesota PCA ice records
EPA Impairment Status
South Long Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN18-0136-00 · Official waterbody report
Nearby Lakes in Crow Wing County
Frequently asked questions about South Long Lake
Where is South Long Lake?
- South Long Lake is a lake in Crow Wing County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of South Long Lake?
- South Long Lake in Crow Wing County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 9 ft visibility. Phosphorus: 24 µg/L. Chlorophyll-a (algae): 8.8 µg/L. Maximum depth: 47 ft. Surface area: 1309.05 acres.
Is South Long Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. South Long Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
What is the water temperature of South Long Lake?
- South Long Lake typically sits around 71°F at the surface in September, from 37 EPA Water Quality Portal field readings (2022–2025). That is a typical value for the month, not a live reading.
How deep is South Long Lake?
- South Long Lake has a maximum depth of 47 feet. The lake covers 1309.05 acres.
What fish are in South Long Lake?
- Fish species found in South Long Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. South Long Lake is located in Crow Wing County, Minnesota.
What did the DNR fisheries survey find at South Long Lake?
- Minnesota DNR's Standard Survey on July 21, 2025 caught 4.83 walleye per gill net at South Long Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows South Long Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
When does South Long Lake thaw?
- South Long Lake typically has ice-out around Apr 16. Ice typically forms around Nov 27. The open water season is approximately 225 days.
Are there boat ramps on South Long Lake?
- South Long Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include South Long Lake. Public access is listed as yes.
Can I fish at South Long Lake?
- South Long Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. 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 South Long 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 Crow Wing County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Brainerd Lakes area
Top lakes and where to stay in the Mille Lacs Area area
Where to stay at Minnesota's top lakes, each with its readings
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 South Long Lake
Other Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Compare South Long Lake With Nearby Lakes
Where this data comes from
430 measurements from 5 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA430 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (5)
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
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