Lake Decatur
Lake Decatur in Macon County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 2904 acres.
- Area
- 2,904 acres
- Public access
- Yes
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Why Lake Decatur has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Lake Decatur, no water-quality sampling on record for this lake.
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by Illinois EPA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Lake Decatur is a 2,904-acre lake in Macon County, Illinois. Limited fish-species data available. Public access is available with 2 public boat landings.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled recent years. Grade methodology: LakeQuality methodology.
Watch Lake Decatur water quality
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Swimming Safety
Not ratedElevated nutrients
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Lake Decatur
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Trophic State Index: undefined.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) |
Where to stay near Lake Decatur
Compare lakeside cabins, hotels, and vacation rentals near Lake Decatur in Macon 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 Lake Decatur
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 2,904 acres |
| Public Access | Yes |
No bathymetric survey has been published for Lake Decatur, so its depth is not documented here.
Recreation & Access
- Lake DecaturPublic
- Lake DecaturPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Lake Decatur
Nearby Lakes in Macon County
Frequently asked questions about Lake Decatur
Where is Lake Decatur?
- Lake Decatur is a lake in Macon County, Illinois. LakeQuality has not rated this lake (UNRATED) — no water-quality sampling on record for this lake.
What is the water quality grade for Lake Decatur?
- Lake Decatur in Macon County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 2904 acres.
Is Lake Decatur safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Lake Decatur is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Are there boat ramps on Lake Decatur?
- Lake Decatur has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Lake Decatur, Lake Decatur. Public access is listed as yes.
Explore Lake Decatur across LakeQuality
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Where this data comes from
Measurements for Lake Decatur come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Other records on this page
Named boat-access points from the USGS National Boat Ramps inventory