Lake Oahe Pierre, South Dakota and extends nearly as far north as Bismarck, North Dakota. Mobridge, South Dakota is located on the eastern shore of the central portion of the lake. Bridges over Lake Oahe include US Route 212 west of Gettysburg, South Dakota and US Route 12 at Mobridge. The former town of Forest City has been flooded beneath Lake Oahe, about 9 miles west of Gettysburg. Prehistoric archaeological sites have been explored in the area, including Molstad Village near Mobridge. It dates to before the emergence of the Arikara, Hidatsa and Mandan as separate peoples, and has been designated as
Perunchani Dam of the reservoir. The dam is located about from Nagercoil, the administrative headquarters-town of Kanyakumari District, and about from the town of Kulasekharam. The average annual rainfall in the catchment is , and the average annual yield at the dam site is . The dam was constructed between 1948–1953 by the then State of Travancore-Cochin. The height of the straight gravity masonry dam above the deepest foundation is , with Full Reservoir Level (FRL) at , which is also the Maximum Water Level (MWL). The dam is long. The gross storage capacity of the reservoir is at the FRL, which