Thornapple Flowage

Rusk County, Wisconsin

OverviewFacts & Figures

Physical Characteristics

Surface Area (Acres)266
Maximum Depth (ft)19
Mean Depth (ft)9
Shoreline (miles)—
Bottom Composition35% sand, 50% gravel, 10% rock, 5% muck
Water Clarity — Secchi Depth (ft)—
Trophic Status—
Drainage BasinDRAINAGE
Lake Classflowage
Public Access—
Township—
GPS Coordinates45.41700° N, 91.19010° W
WBIC (DNR ID)2227500

Fish Species

8 species documented

AbundantCommonPresentRare
SpeciesAbundanceLast Survey
Smallmouth BassCommon—
WalleyeCommon—
CatfishPresent—
Largemouth BassPresent—
MuskyPresent—
Northern PikePresent—
PanfishPresent—
SturgeonPresent—

Boat Landings

2 landings

NameTypeRampTrailersFee♿
Port Arthur Boat RampRAMP—6-10NoYes
Thornapple Flowage AccessRAMP—1-5NoNo

Invasive Species

Invasive species have been documented in or near this lake. Please clean, drain, and dry all watercraft and equipment before leaving to prevent spread.

SpeciesStatusFirst Detected
Purple LoosestrifeConfirmed—
Rusty CrayfishConfirmed—

Data sourced from Wisconsin DNR lake surveys. Last scraped: 4/30/2026.