In the
Great Lakes Region, Chamberlain is located in
Brule County (of which it is the county seat) southeast of
Pierre next to
Oacoma, with which it shares a chamber of commerce. The two cities lie along I-90 on the banks of the
Missouri River and
Lake Francis Case.
Chamberlain-Oacoma rests in the heart of prime pheasant and grouse, deer and waterfowl country and boasts one of the highest annual bird harvests.
The population estimate for July 1, 1998 was 2,411, an increase of 64 since 1990.