Lake of the Falls
Iron County, WisconsinMesotrophic
Lake of the Falls comes in at a B on the grading rubric — a respectable showing for a Wisconsin lake of its size and depth. Clarity is the limiting factor — phosphorus is reasonable but suspended particles or algal cells keep water transparency below Wisconsin norms.
A TSI near 50 places Lake of the Falls in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. A maximum depth of 23 ft puts Lake of the Falls in the middle of Wisconsin's depth distribution. The lake's 297 acres and partial shoreline records put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Lake of the Falls ranks 16 of 33 in Iron County — solidly in the upper half of the local distribution.
Lake of the Falls has at least one documented invasive species (Banded Mystery Snail), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. Walleye are documented at Lake of the Falls, one of 6 fish species on record for the lake. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-10-13. Grade methodology: LakeGrade methodology.
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Murky, only visible to about 5.4 ft. Phosphorus level: 19.6 µg/L. Trophic State Index: 50.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.4 ft | D |
| Phosphorus | 19.6 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 50 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 23 ft |
| Surface Area | 297 acres |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for Lake of the Falls (14-day solunar calendar)
→ Is it safe to eat fish from Lake of the Falls? (mercury & PFAS guide)
→ Lake of the Falls fishing regulations (limits, seasons, special rules)
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.025 m/yr | 6 |
| Phosphorus | → Stable | -0.01 µg/L/yr | 5 |
Location
County Ranking
Ranked #16 of 33 lakes in Iron County
Cleaner Lakes Within 30 Miles
Lake of the Falls holds Grade B. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Iron County
More Wisconsin Lake Rankings
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2004. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Reservoir Info (USACE NID)
Lake of the Falls is a man-made reservoir impounded by the Lake of The Falls (completed 1895), built primarily for recreation on the TURTLE; earth-type dam, 12 ft tall and 300 ft long.
- Surface area
- 338 ac
- Normal storage
- 1,000 ac-ft
- Max storage
- 3,700 ac-ft
- Drainage area
- 136 sq mi
- Hazard class
- Low
- Owner
- Iron County - Forestry & Parks Department
Source: USACE National Inventory of Dams, NID ID WI00618 · Operator website
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-10-13
Monitoring stations: 1