Little Grassy Lake
Little Grassy Lake in Williamson County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 905 acres.
- Area
- 905 acres
Next lake in Williamson County
Swipe left or right on this bar to open the next or previous lake.
Why Little Grassy Lake 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 Little Grassy Lake, 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.
Little Grassy Lake is a 905-acre lake in Williamson County, Illinois.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled recent years. Grade methodology: LakeQuality methodology.
Watch Little Grassy Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Not ratedElevated nutrients
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Little Grassy Lake
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 Little Grassy Lake
Compare lakeside cabins, hotels, and vacation rentals near Little Grassy Lake in Williamson 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 Little Grassy Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Illinois’s top lakes →
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 905 acres |
No bathymetric survey has been published for Little Grassy Lake, so its depth is not documented here.
Fishing Little Grassy Lake
Nearby Lakes in Williamson County
Frequently asked questions about Little Grassy Lake
Where is Little Grassy Lake?
- Little Grassy Lake is a lake in Williamson 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 Little Grassy Lake?
- Little Grassy Lake in Williamson County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 905 acres.
Is Little Grassy Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Little Grassy Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Explore Little Grassy Lake across LakeQuality
More Illinois Lake Rankings
Other Lakes in Illinois
Where this data comes from
Measurements for Little Grassy Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.