Lake Oahe Lake Oahe Lake Oahe (oh-WAH'-hee) is a large reservoir behind Oahe Dam on the Missouri River; it begins in central South Dakota and continues north into North Dakota in the United States. The lake has an area of and a maximum depth of . By volume, it is the fourth-largest reservoir in the US. Lake Oahe has a length of approximately and has a shoreline of . 51 recreation areas are located along Lake Oahe, and 1.5 million people visit the reservoir every year. The lake is named for the 1874 Oahe Indian Mission. Lake Oahe begins just north of
Beaver Dam, Arizona to Arizona State Route 389 (which is paved) — and even at that, is connected only to the rest of the "Arizona Strip" (that part of Arizona separated from the rest of the state by the Grand Canyon), not to Arizona at large. The Virgin River Gorge is located just to the east of Beaver Dam. The Post Office is located in Beaver Dam on McKnight Boulevard. Fire Station No. 1 is located in Beaver Dam (No. 2 is located in Desert Springs, and No. 3 is located in Scenic). Beaver Dam has a large population of "snowbirds" (retirees from