 In north @-@ central Montana , some 1 @,@ 100 @,@ 000 acres ( 4 @,@ 500 km2 ) along over 125 miles ( 201 km ) of the Missouri River , centering on Fort Peck Lake , comprise the Charles M. Russell National Wildlife Refuge . The wildlife refuge consists of a native northern Great Plains ecosystem that has not been heavily affected by human development , except for the construction of Fort Peck Dam . Although there are few designated trails , the whole preserve is open to hiking and camping . 
