Boulder Lake

Boulder Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Hubbard County. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. A maximum depth of 28 ft puts Boulder Lake in the middle of Minnesota's depth distribution. Boulder Lake covers 341 acres alongside 4.9 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Boulder Lake sits at rank 48 of 77 in Hubbard County, in the lower half of the local distribution.

An invasive species record — faucet snail — has been logged at Boulder Lake; Minnesota PCA maintains the official infested-waters list. The fishery includes walleye alongside the lake's other 14 documented species — a notable draw for Minnesota anglers. Public access is available — the lake is on the Minnesota PCA public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.