
Randolph County Lake Quality
Illinois, 8 lakes, measured by Illinois EPA
Randolph County has 8 monitored lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. 3 of those lakes carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. The monitored lakes here are mostly shallow, productive basins where summer algae is common; each lake page shows its own readings beside the EPA condition class.
Most of the county's monitored lakes are shallow, under 50 feet, which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Randolph Lake has the lowest nutrient and algae readings in the county.
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Quick Answers for Randolph County
Planning a trip? Check special fishing regulations for Randolph Lake — or check the official Illinois fishing regulations.
All Lakes in Randolph County
8 lakes · 3 ranked on readings, 5 without enough sampling3 lakes ranked on readings · 5 without enough sampling, hidden
| # | Lake | Clarity | Phosphorus | Algae | Trophic | Max Depth | Access |
|---|---|---|---|---|---|---|---|
| 1 | Randolph LakeRandolph | 1.7 ft | 87.5 µg/L | 44.9 µg/L | No recent samples | No recent samples | ✓ Public |
| 2 | Sparta Northwest LakeRandolph | 2.6 ft | 44.5 µg/L | 32.5 µg/L | No recent samples | No recent samples | ✓ Public |
| 3 | Coulterville LakeRandolph | 2.7 ft | 452.5 µg/L | 51 µg/L | No recent samples | No recent samples | Not recorded |
| Randolph County LakeRandolph | No recent samples | No recent samples | No recent samples | No recent samples | 35 ft | ✓ Public | |
| West C Streamline LakeRandolph | No recent samples | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Old City ReservoirRandolph | No recent samples | No recent samples | No recent samples | No recent samples | 16 ft | ✓ Public | |
| New City ReservoirRandolph | No recent samples | No recent samples | No recent samples | No recent samples | 12 ft | ✓ Public | |
| Baldwin LakeRandolph | No recent samples | No recent samples | No recent samples | No recent samples | 48 ft | ✓ Public |
NR = no nutrient or algae reading on record. The measurements are published as the authority reports them. Where the data comes from.
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Source: the Illinois Environmental Protection Agency. See data sources.