1 The population which is dispersed from large cities to relieve congestion and overcrowding, and, possibly, unemployment. It occurs with redevelopment in the city where new building is at much lower densities so that some people—the overspill—cannot be housed in the city.

2 The condition of a fluvio-glacial lake when water levels rise above the barrier impounding it; see Kaiser et al. (2007) Earth Surf. Procs Ldfms 32, 10.

3 The dispersal—whether spontaneous or planned—of population in response to congestion, overcrowding, and high property prices. Overspill in Canada reflects the ongoing search for cheaper accommodation, by those who have been hardest hit by the crisis in affordable housing that has characterized Canada's largest and fastest-growing cities since the 1980s (Mitchell et al. (2004) Canad. Geogr./Géogr. canad. 48, 2).