Lake Delton vs Mirror Lake
Water quality, depth, fish species, and recreation comparison.
Mirror Lake has a higher water quality grade (D, Poor) than Lake Delton (F, Very Poor). Both are in Sauk County, Wisconsin.
Lake Delton and Mirror Lake are both in Wisconsin — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. The grades are close: Lake Delton (F) and Mirror Lake (D) are within one letter of each other on the LakeGrade rubric. The per-parameter sub-grades below will show where the small differences actually live.
With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.
Lake Delton
Very murky, less than 2.5 ft of visibility.
Mirror Lake
Murky, only visible to about 4.6 ft.
Side-by-Side Metrics
| Metric | Lake Delton | Mirror Lake |
|---|---|---|
| Overall Grade | F (Very Poor) | D (Poor) |
| Water Clarity | 2.5 ft | 4.6 ft |
| Phosphorus | No data | 65.4 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | - | - |
| Surface Area | 267 acres | 137 acres |
| Public Access | Unknown | Unknown |
| Fish Species | 0 | 0 |
| Trophic State | eutrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Mirror Lake wins on overall water quality with a Grade D versus Lake Delton's Grade F. Water clarity: 4.6 ft vs 2.5 ft. For fishing diversity, Mirror Lake also leads with 0 species.