The Hudson Plains ecozone curves around Hudson Bay and James Bay, extending from northeastern Manitoba to western Quebec, with the largest portion in northern Ontario. A lowland rising slowly from sea level, and rarely reaching more than 500 metres in elevation, this ecozone is poorly
drained and contains the largest continuous wetlands on the planet. It has a cold continental climate, with short, cool summers and long, very cold
winters.
The landscape is dominated by peatlands. Trees are relatively few, often occurring in sparse stunted stands. However, on better drained sites, such as beach ridges, river levees and raised glacial deposits, black spruce (occasionally with white spruce) often attains very good growth.