Greenwood Lake is a large, deep lake with numerous rocky shoals located in the Canadian Shield ecoregion. Its depths vary greatly and the lake contains two deep basins, one near the center and the other in the eastern bay. Greenwood is found off the Gunflint Trail 19 miles northeast of Grand Marais and is within the Superior National Forest, just south of the Boundary Waters Canoe Area Wilderness. It has a comparatively small watershed made up of forest and wetlands. The watershed around the lake is relatively undeveloped as is much of the shoreline of the lake. Based on records from the Water Plan Coordinator for the Cook County Soil and Water District there are 55 total home-sites with residents on the lake.
Because it is oligotrophic (nutrient poor), zooplankton biomass and densities are among the lowest of all Sentinel Lakes. The invasive Spiny Water Flea was first detected in Greenwood Lake in 2005 and has become well established. Continued monitoring of the zooplankton community will be important to identify impacts of Spiny Water Flea and potential consequences for the fish community, including gamefish populations.
The fish community of Greenwood Lake is comprised of warm-, cool-, and cold-water species including Brook Trout, Green Sunfish, Lake Trout, Lake Whitefish, Northern Pike, Rainbow Trout, Smallmouth Bass, Splake, Cisco, Walleye, Yellow Perch, White Sucker, Creek Chub, and Golden Shiner. The lake’s relatively large size and depth provide excellent habitat for cold-water fish species such as Cisco, Lake Whitefish, and Lake Trout. The Lake Trout population is self-sustaining and was last stocked in 1993.
Greenwood Lake was added to the Sentinel Lakes network in 2012 to provide an additional deep oligotrophic lake that supported Lake Trout.