Where is Big Marsh Lake?

Big Marsh Lake is a lake in Cook County, Illinois. Its water-quality measurements are published by Illinois EPA and shown on this page as reported.

Big Marsh Lake

Cook County, IllinoisView map Directions

No nutrient or algae sampling on record from Illinois EPA for this lake.

Limited data

See the measurements Directions Where to stay

Big Marsh Lake in Cook County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported.

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Big Marsh Lake is a lake in Cook County, Illinois. Overall water quality is declining over recent sampling years.

Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2023-04-26. Methodology: how these readings are compared.

Swimming conditions

No reading

Limited data

Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.

Whether Big Marsh Lake is safe to swim in today is a call for the Illinois Environmental Protection Agency and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.

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Water quality measurements for Big Marsh Lake

These are the measurements Illinois EPA publishes for Big Marsh 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.

Ask about Big Marsh Lake

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

Stays via Stay22

Stays near Big Marsh Lake

Compare lakeside cabins, hotels, and vacation rentals near Big Marsh Lake in Cook County, Illinois — 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 Big Marsh Lake

Prices for Oct 23–25, 4 adults. Change dates on the map below.

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Fishing Big Marsh Lake

→ Big Marsh Lake fishing regulations (limits, seasons, special rules)

Water quality readings over time

2 seasons of samples on record (2021–2023). Calling a direction takes at least 4 years of the same measurement.

Water clarity
Worsening
2 years

Regulated Pollution Sources Nearby

3 EPA-permitted facilities operate within about 5 miles of Big Marsh Lake under Clean Water Act (NPDES) discharge permits. 2 facilities have a reported Clean Water Act violation in the past three years.

Cargill Industrial Specialities
Chicago · 1.4 mi away · NPDES IL0056057
Recent violation
Pvs Chemical Solutions Inc
Chicago · 1.6 mi away · NPDES IL0002640
Recent violation
Land&Lakes Company
Chicago · 0.2 mi away · NPDES IL0067237

Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.

Nearby Lakes in Cook County

Dead Stick Pond—View →Lake Calumet4.1 ft clear · Mesotrophic1.2 miView →Flatfoot Lake6.2 ft clear · Eutrophic2.8 miView →Wolf Lake—View →Burnham Prairie Marsh West Lake3.5 miView →Lake Cottage Grove—View →

Frequently asked questions about Big Marsh Lake

Where is Big Marsh Lake?: Big Marsh Lake is a lake in Cook County, Illinois. Its water-quality measurements are published by Illinois EPA and shown on this page as reported.
What is the water quality of Big Marsh Lake?: Big Marsh Lake in Cook County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported.
Is Big Marsh Lake safe to swim in?: Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.

Explore Big Marsh Lake across LakeQuality

Lake Fishing Forecast

Species activity outlook by water temperature and season

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Planning a trip around Indiana Dunes?

Big Marsh Lake is about 25 miles from Indiana Dunes National Park. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.

Best time to visit Indiana Dunes →

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Where this data comes from

1 measurement from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

USGS Illinois Water Science CenterUSGS-IL1 sample · 2023

Analytical methods

Secchi disk method

Monitoring station identifiers (1)

USGS-414124087341801

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.