Portsmouth Mine Pit Lake, sometimes called the Portsmouth Pit, is the deepest lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 in Minnesota

Minnesota

Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...

 at over 450 feet (137 m), according to the most recent Minnesota DNR data. The 120 acres (48.6 ha) artificial lake is a former iron mining pit in the Cuyuna Range

Cuyuna Range

The Cuyuna Range is an iron range to the southwest of the Mesabi Range, largely within Crow Wing County, Minnesota. It lies along a line between Brainerd and Aitkin, although those communities are not mining towns....

 that has since filled with water.

The Portsmouth Mine Pit is part of the Cuyuna Country State Recreation Area

Cuyuna Country State Recreation Area

Cuyuna Country State Recreation Area is a state park unit of Minnesota, USA, being developed to rehabilitate a portion of the Cuyuna Range where mining pits and piles of waste rock were left behind after decades of open-pit mining for iron ore...

, located in Crow Wing County

Crow Wing County, Minnesota

Crow Wing County is a county located in the U.S. state of Minnesota. As of 2010, the population was 62,500. Its county seat is Brainerd.-Geography:...

. The lake is within Crosby

Crosby, Minnesota

As of the census of 2000, there were 2,299 people, 989 households, and 554 families residing in the city. The population density was 755.0 people per square mile . There were 1,081 housing units at an average density of 355.0 per square mile...

-Ironton

Ironton, Minnesota

As of the census of 2000, there were 498 people, 231 households, and 130 families residing in the city. The population density was 333.2 people per square mile . There were 263 housing units at an average density of 176.0 per square mile . The racial makeup of the city was 99.40% White, 0.40%...

 city limits.

In the last five years, the Minnesota DNR has repeatedly stocked the lake with brook

Brook trout

The brook trout, Salvelinus fontinalis, is a species of fish in the salmon family of order Salmoniformes. In many parts of its range, it is known as the speckled trout or squaretail. A potamodromous population in Lake Superior are known as coaster trout or, simply, as coasters...

 and rainbow

Rainbow trout

The rainbow trout is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea run rainbow trout usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species....

 trout

Trout

Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...

.

On August 19, 1957, the mine pit, then not yet filled with water, served as launch site for a big stratospheric balloon; the second flight of the Air Force's Project Manhigh

Project Manhigh

Project Manhigh along with Project Excelsior was a pre-Space Age military project that took men in balloons to the middle layers of the Earth’s stratosphere.-History:...

.