The Okanagan Basin spans two countries and comprises the basin of Okanagan Lake, the Okanogan River and tributary valleys such as that of the Similkameen and Chelan Rivers. In Canada the basin constitutes two distinct regions within British Columbia, the Similkameen Country to the west and the main Okanagan region running from the communities of Osoyoos in the south to Armstrong in the north – incorporating most of the three Okanagan regional districts and is usually known as "the Okanagan" or as the Okanagan Valley or the Okanagan Country. In the United States, the Okanogan Country is the western, lowland core of Okanogan County, which like its Canadian counterpart has a history and economy based on ranching, gold, fruit orcharding and vineyards, but the basin includes Lake Chelan and other flanking valleys.