Long Lake is a lake in Codington County, South Dakota. Its water-quality measurements are published by SD DANR and shown on this page as reported.

Long Lake

Codington County, South Dakota2,489 acresView map Directions

No nutrient or algae sampling on record from SD DANR for this lake.

Area

2,489 acres

Surface area

Impaired · Mercury

See the measurements Directions Where to stay

Long Lake in Codington County, South Dakota has water-quality measurements published by SD DANR, shown here as reported. Surface area: 2489 acres.

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Long Lake is a 2,489-acre lake in Codington County, South Dakota.

Source: EPA Water Quality Portal sampling records, SD DANR. Methodology: how these readings are compared.

What Long Lake is good for

From access and monitoring records, not editorial picks.

Big water2,489 acres

Swimming conditions

No reading

Not rated

Nutrient and algae readings are not a swimming clearance. Long Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.

Whether Long Lake is safe to swim in today is a call for the South Dakota Department of Agriculture and Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.

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Water quality measurements for Long Lake

These are the measurements SD DANR publishes for Long Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.

No clarity data. TSI undefined.

Ask about Long Lake

Answers come straight from the public measurements and survey records on this page.

Lake Details

Surface area

2,489 acres

No bathymetric survey has been published for Long Lake, so its depth is not documented here.

Stays via Stay22

Stays near Long Lake

Compare lakeside cabins, hotels, and vacation rentals near Long Lake in Codington County, South Dakota — 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 Long Lake

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Follow Long Lake’s readings

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Fishing Long Lake

→ Long Lake fishing regulations (limits, seasons, special rules)

EPA Impairment Status

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

Mercury

Designated uses not supporting: Aquatic life.

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit SD-BS-L-LONG_COD_01 · Official waterbody report

Nearby Lakes in Codington County

Blythe Slough1.8 miView →Stink Lake2.5 miView →Medicine Lake4.3 miView →Horseshoe Lake4.7 miView →Cooley Lake5.5 miView →Lake Nicholson6.3 miView →

Frequently asked questions about Long Lake

Where is Long Lake?: Long Lake is a lake in Codington County, South Dakota. Its water-quality measurements are published by SD DANR and shown on this page as reported.
What is the water quality of Long Lake?: Long Lake in Codington County, South Dakota has water-quality measurements published by SD DANR, shown here as reported. Surface area: 2489 acres.
Is Long Lake safe to swim in?: Nutrient and algae readings are not a swimming clearance. Long Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.