The Canadian Prairies are part of a vast sedimentary plain covering much of Alberta, southern Saskatchewan, and southwestern Manitoba, as well as much of the region between the Rocky Mountains and the Great Slave and Great Bear lakes in Northwest Territories. The plains generally describes the expanses of (largely flat) arable agricultural land which sustain extensive grain farming operations in the southern part of the provinces. Despite this, some areas such as the Cypress Hills and the Alberta Badlands are quite hilly and the prairie provinces contain large areas of forest such as the Mid-Continental Canadian forests. The size is roughly ~.