1
CMark Twain Lake
Monroe County, Wisconsin · 25.7 mi from Shelbyville Lake
- +Two grade letters higher (F → C)
- ++2.8 ft water clarity
- +Lower phosphorus (36 vs 252.5 µg/L)
Cleaner Lakes Than Shelbyville Lake
5 higher-graded lakes within 30 miles, ranked by grade improvement and proximity.
Shelbyville Lake carries a Grade F (Very Poor) water quality score. Within 30 miles, 5 lakes hold a higher grade. Mark Twain Lake (Monroe County, Grade C, 25.7 mi away) is the closest meaningful upgrade.
2
CMark Twain Lake Indian Creek Arm
Ralls County, Wisconsin · 26.4 mi from Shelbyville Lake
- +Two grade letters higher (F → C)
- ++2.8 ft water clarity
- +Lower phosphorus (31.5 vs 252.5 µg/L)
3
DHunnewell Lake
Shelby County, Wisconsin · 12.2 mi from Shelbyville Lake
- +Higher grade (F → D)
- ++2.2 ft water clarity
- +Lower phosphorus (36 vs 252.5 µg/L)
4
DLong Branch Lk. Lake
Macon County, Wisconsin · 24.8 mi from Shelbyville Lake
- +Higher grade (F → D)
- +Lower phosphorus (43.5 vs 252.5 µg/L)
5
DHenry Sever Lake
Knox County, Wisconsin · 14.3 mi from Shelbyville Lake
- +Higher grade (F → D)
- ++1.1 ft water clarity
- +Lower phosphorus (58 vs 252.5 µg/L)
How this list is built
Every lake on LakeQuality has a calculated grade from EPA Water Quality Portal samples — secchi depth, total phosphorus, and chlorophyll-a measured against Metropolitan Council thresholds. To suggest cleaner alternatives, we filter lakes within 30 miles to those with a strictly higher numeric score, then rank by grade improvement with a small proximity tiebreak. Cross-state and limited-data lakes are excluded so the list stays locally relevant.