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

Are there boat ramps on Lake Sinai?

Lake Sinai has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Sinai Public Water Access. Public access is listed as yes.

Can I fish at Lake Sinai?

Lake Sinai 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 South Dakota's fish and wildlife agency, so check its current regulations before you go.

Lake Sinai

Brookings County, South Dakota1,790 acresView map Directions

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

Area

1,790 acres

Surface area

Shoreline

16.5 mi

Measured length

Impaired · Mercury
Public access
Limited data

See the measurements Directions Where to stay

Lake Sinai in Brookings County, South Dakota has water-quality measurements published by SD DANR, shown here as reported. Surface area: 1790 acres.

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Lake Sinai is a 1,790-acre lake in Brookings County, South Dakota. Limited fish-species data available. Public access is available with 1 public boat landing.

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

What Lake Sinai is good for

From access and monitoring records, not editorial picks.

Boat launch1 documented ramp
Big water1,790 acres

Swimming conditions

No reading

Limited data

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

Whether Lake Sinai 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 Lake Sinai

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

No clarity data.

Ask about Lake Sinai

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

Lake Details

Surface area

1,790 acres

Shoreline

16.5 mi

Public access

Yes

Listed by SD DANR

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

Recreation & Access

Boat Landings

Yes

Public Access

Sinai Public Water AccessPublic

Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps

Stays via Stay22

Stays near Lake Sinai

Compare lakeside cabins, hotels, and vacation rentals near Lake Sinai in Brookings 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 Lake Sinai

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Fishing Lake Sinai

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

EPA Impairment Status

Lake Sinai 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-SINAI_01 · Official waterbody report

Nearby Lakes in Brookings County

Brush Lake4.4 miView →Nelson Slough4.4 miView →Pederson Slough6.6 miView →Lake Mitchell—View →Mortimer Slough—View →Moe Slough—View →

Frequently asked questions about Lake Sinai

Where is Lake Sinai?: Lake Sinai is a lake in Brookings 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 Lake Sinai?: Lake Sinai in Brookings County, South Dakota has water-quality measurements published by SD DANR, shown here as reported. Surface area: 1790 acres.
Is Lake Sinai safe to swim in?: Nutrient and algae readings are not a swimming clearance. Lake Sinai is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Are there boat ramps on Lake Sinai?: Lake Sinai has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Sinai Public Water Access. Public access is listed as yes.
Can I fish at Lake Sinai?: Lake Sinai 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 South Dakota's fish and wildlife agency, so check its current regulations before you go.