Jack Lake
Jack Lake in Mason County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 1501 acres.
- Area
- 1,501 acres
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Why Jack 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 Jack 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.
Jack Lake is a 1,501-acre lake in Mason County, Illinois.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled recent years. Grade methodology: LakeQuality methodology.
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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 Jack 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 Jack Lake
Compare lakeside cabins, hotels, and vacation rentals near Jack Lake in Mason 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 Jack Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 1,501 acres |
No bathymetric survey has been published for Jack Lake, so its depth is not documented here.
Fishing Jack Lake
Nearby Lakes in Mason County
Frequently asked questions about Jack Lake
Where is Jack Lake?
- Jack Lake is a lake in Mason 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 Jack Lake?
- Jack Lake in Mason County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 1501 acres.
Is Jack Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Jack Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
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Where this data comes from
Measurements for Jack Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.