Largest Lakes by Surface Area

Rainy Lake in Koochiching County, MN, is the largest on our index at 210,200 acres. (We rank inland lakes — the Great Lakes are excluded.)

Surface area comes from state DNR lake surveys and, for reservoirs, US Army Corps of Engineers (USACE) National Inventory of Dams records. Area is reported in acres at normal pool elevation. Reservoirs rise and fall with management, so their listed area is the long-term normal rather than a single-day reading.

It varies more within a big lake than between lakes. A large lake can have a clean, deep main basin and a murky, algae-prone bay fed by a tributary, so a single reading can hide wide swings. Surface area alone does not predict quality — depth, watershed land use, and flushing rate matter far more.

This ranking covers inland lakes and reservoirs. The Great Lakes dwarf every inland lake by orders of magnitude, so including them would crowd out the lakes anglers and swimmers actually visit. We rank the largest inland waters across US lakes with nutrient and algae readings instead.