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B

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.

Reviewed by LakeQuality Editorial Team · Updated

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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.

MetricValueGrade
Water Clarity (Secchi Depth)5.4 ftD
Phosphorus19.6 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)50Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Maximum Depth23 ft
Surface Area297 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.

Banded Mystery SnailChinese Mystery Snail

Water Quality Trend: Stable

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Stable-0.025 m/yr6
Phosphorus Stable-0.01 µg/L/yr5
See year-by-year chart →

Location

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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

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2004. 1 station on file (most recent sample 2025).

DNR Assessment
Excellent · Shallow Lowland lake
Trophic State Index 44 (mesotrophic) · 5-year average

Fish Species (DNR-rated)

Musky(Common)Panfish(Common)Northern Pike(Common)Walleye(Common)Largemouth Bass(Present)Smallmouth Bass(Present)

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