Raccoon Lake
Marion County, Illinois730 acresView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- Impaired · Mercury
- #4 of 6 in the county
- 56 ft max depth
- Public access
- Limited data
Raccoon Lake in Marion County, Illinois has a water quality grade of F (Algae-prone). Water clarity: 1.2 ft visibility. Phosphorus: 285 µg/L. Chlorophyll-a (algae): 73.5 µg/L. Surface area: 730 acres.
- Clarity
- 1.2 ft
- Typical in August
- 82°F
- Max depth
- ~56 ft est.
- Area
- 730 acres
- Type
- Hypereutrophic
- Public access
- Yes
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Raccoon Lake is a 730-acre highly nutrient-loaded hypereutrophic lake in Marion County, Illinois with an estimated average depth of about 56 feet. Water quality is graded F based on 2 sampling years through 2021. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 5 other monitored lakes in Marion County, Raccoon Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2021-11-09. Grade methodology: LakeQuality methodology.
What Raccoon Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The F is nutrients and algae, not a swimming clearance. Raccoon Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), pesticides, pCBs. Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Very murky, less than 1.2 ft of visibility. Phosphorus 285 µg/L. Chlorophyll-a 73.5 µg/L. TSI 78. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.2 ft | Not graded |
| Phosphorus | 285 µg/L | Poor |
| Chlorophyll-a (Algae) | 73.5 µg/L | Poor |
| Trophic State Index (TSI) | 78 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Water Temperature
Raccoon Lake typically sits around 82°F at the surface in August. Summer average is about 81°F. Usually warmest in Jul (about 85°F) and coldest in Nov (about 54°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 53 field readings (2011–2021) via the EPA Water Quality Portal. See the full Raccoon Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~56 ft est. |
| Average Depth | ~11 ft est. |
| Surface Area | 730 acres |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Illinois has not published bathymetry for Raccoon Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Raccoon LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Raccoon Lake
Reservoir Info (USACE NID)
Raccoon Lake is a man-made reservoir impounded by the Raccoon Lake Dam (completed 1943), built primarily for water supply on the RACCON CREEK; earth-type dam, 29 ft tall and 1,480 ft long.
- Surface area
- 730 ac
- Normal storage
- 4,709 ac-ft
- Max storage
- 6,700 ac-ft
- Drainage area
- 48.5 sq mi
- Hazard class
- High
- Owner
- CITY OF CENTRALIA
Source: USACE National Inventory of Dams, NID ID IL00242 · Operator website
EPA Impairment Status
Raccoon Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IL_ROK · Official waterbody report
Regulated Pollution Sources Nearby
5 EPA-permitted facilities operate within about 5 miles of Raccoon Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 3 facilities have a reported Clean Water Act violation in the past three years.
- Centralia Stp, City OfCentralia · 4.9 mi away · NPDES IL0027979MajorRecent violation
- Sandoval Stp, Village OfSandoval · 4.4 mi away · NPDES IL0030961Recent violation
- Illinois Central Railroad - Centralia YardCentralia · 4.4 mi away · NPDES IL0000779Recent violation
- Centralia Wtp, City OfCentralia · 2.4 mi away · NPDES IL0001252
- United Parcel Service - CentraliaCentralia · 3.5 mi away · NPDES IL0071242
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.
County Ranking
Ranked #4 of 6 lakes in Marion County
Nearby Lakes in Marion County
Frequently asked questions about Raccoon Lake
Where is Raccoon Lake?
- Raccoon Lake is a lake in Marion County, Illinois. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Raccoon Lake?
- Raccoon Lake in Marion County, Illinois has a water quality grade of F (Algae-prone). Water clarity: 1.2 ft visibility. Phosphorus: 285 µg/L. Chlorophyll-a (algae): 73.5 µg/L. Surface area: 730 acres.
Is Raccoon Lake safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Raccoon Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), pesticides, pCBs. Check local advisories before you swim.
What is the water temperature of Raccoon Lake?
- Raccoon Lake typically sits around 82°F at the surface in August, from 53 EPA Water Quality Portal field readings (2011–2021). That is a typical value for the month, not a live reading.
How deep is Raccoon Lake?
- No published bathymetric survey covers Raccoon Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 56 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 730 acres.
Are there boat ramps on Raccoon Lake?
- Raccoon Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Raccoon Lake. Public access is listed as yes.
Explore Raccoon Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Species activity outlook by water temperature and season
Where to stay at Illinois's top lakes, each with its grade
Very high nutrients, dense algae, poor clarity
Illinois's cleanest and most-polluted lakes, ranked
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Where this data comes from
57 measurements from 3 monitoring stations, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- illinois epa
IL_EPA_WQX57 samples · 2021
Analytical methods
- MEASURED IN FIELD
- Phosphorus by Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (3)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory