Gammarus lacustris is found throughout most of Canada and Alaska north to the Arctic circle, and to latitude 70°N in some areas. It occurs in most of the western and northern USA, with a disjunct population in Oklahoma. It is also found in northwestern Europe (Holsinger, 1972) and Siberia (Zadereev et al, 2010). It is widespread and common in British Columbia.
This species occurs in a variety of cold-water habitats, including lakes, tundra ponds, streams, sloughs, swamps, and springs (Holsinger, 1972). It may also be found in saline habitats (Zadereev et al, 2010).
Note Author: Ian Gardiner