Skip to main content
LakeQuality
Late afternoon sun over Slim Lake, scattering a bright path across wind-textured water

Mason County Lake Quality

Illinois, 21 lakes, measured by Illinois EPA

The county-level average smooths over real differences — a single agricultural watershed near the southwest corner can pull the average down even if the rest of the county runs clean. The 21 monitored lakes in Mason County carry whatever clarity, phosphorus, and chlorophyll-a readings Illinois EPA has published, shown as reported.

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.

Loading map…

Where to stay near Mason County

Top-rated places to stay near Mason County

Prices for Oct 30–Nov 1, 4 adults. Change dates on the map below.

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 trip to Mason County?

Get lake water-quality updates plus the best cabin & lodging deals near Mason County — straight to your inbox. No spam, unsubscribe anytime.

Quick Answers for Mason County

Cleanest lakes in Mason County →Cleanest lakes in Illinois →Best swimming lakes in Illinois →

Planning a trip? Check special fishing regulations for Quiver Lake — or check the official Illinois fishing regulations.

All Lakes in Mason County

21 lakes · 0 ranked on readings, 21 without enough sampling0 lakes ranked on readings · 21 without enough sampling, hidden

#LakeClarityPhosphorusAlgaeTrophicMax DepthAccess
Quiver LakeMasonNo recent samplesNo recent samples140 µg/LNo recent samplesNo recent samples✓ Public
Sand LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Lake ChautauquaMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Matanzas LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samples8 ftNot recorded
Bath LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Moscow LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Bell LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Jack LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Patterson BayMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Wolf LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
River SwaleMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Mound LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Otter LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Wilcox LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Crane LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samples4 ftNot recorded
Cross SloughMasonNo recent samplesNo recent samplesNo recent samplesNo recent samples7 ftNot recorded
Ingram LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Chain LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Liverpool LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
Quiver LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Quiver LakeMasonNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded

NR = no nutrient or algae reading on record. The measurements are published as the authority reports them. Where the data comes from.

Lake Match

Which lake suits how you actually use one?

Six questions — swimming, fishing, quiet, cabins, drive time — and a shortlist of lakes that fit, with the water quality behind each one.

Take the quiz →

Other Counties in Illinois

Winnebago County

7 lakes

DeKalb County

1 lake

Kane County

3 lakes

Perry County

7 lakes

Rock Island County

3 lakes

Jackson County

14 lakes

Browse every Illinois lake, or the full directory of lakes across all United States (49 states), Canada (Ontario, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs..

Source: the Illinois Environmental Protection Agency. See data sources.