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B

Little Long Lake

Forest County, WisconsinLimited DataMesotrophic

Little Long Lake comes in at a B on the grading rubric — a respectable showing for a Wisconsin lake of its size and depth.

Mesotrophic conditions dominate at Little Long Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. Little Long Lake reaches 30 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. The lake's 101 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. Little Long Lake sits at rank 22 of 34 in Forest County, in the lower half of the local distribution.

An invasive species record — Chinese Mystery Snail — has been logged at Little Long Lake; Wisconsin DNR maintains the official infested-waters list. The fishery is bass-led, with 3 documented species across the lake's records. 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 2025-08-27. 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

Good clarity, visible to about 13.1 ft. Trophic State Index: 40.

MetricValueGrade
Water Clarity (Secchi Depth)13.1 ftB
PhosphorusNo data
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)40Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Maximum Depth30 ft
Surface Area101 acres

Fish Species

Click a species to see all Wisconsin and Minnesota lakes where it is found.

→ Best fishing times for Little Long Lake (14-day solunar calendar)

→ Is it safe to eat fish from Little Long Lake? (mercury & PFAS guide)

Little Long Lake 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.

Chinese Mystery SnailPurple Loosestrife

Water Quality Trend: Declining

Based on 2 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-1.88 m/yr2

Location

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County Ranking

Ranked #22 of 34 lakes in Forest County

Cleaner Lakes Within 30 Miles

Little Long Lake holds Grade B. 3 nearby lakes hold higher grades.

Nearby Lakes in Forest County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1994. 1 station on file (most recent sample 2025).

Fish Species (DNR-rated)

Panfish(Common)Largemouth Bass(Common)Northern Pike(Common)

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2025-08-27

Monitoring stations: 1