▁north ▁boundary ▁line ▁of ▁the ▁state ▁of ▁South ▁Dak ota . ▁Its ▁terrain ▁consists ▁of ▁semi - ar id ▁low ▁rolling ▁hills . ▁Its ▁terrain ▁generally ▁s lop es ▁east ward , ▁and ▁its ▁highest ▁point ▁is ▁on ▁its ▁upper ▁west ▁boundary ▁line , ▁at ▁ 3 , 0 0 2 ' ▁( 9 1 5 m ) ▁AS L . ▁The ▁county ▁has ▁a ▁total ▁area ▁of ▁, ▁of ▁which ▁ ▁is ▁land ▁and ▁ ▁( 0 . 1 %) ▁is ▁water . ▁ ▁Ad j acent ▁count ies ▁▁ ▁Het ting er ▁County ▁– ▁north ▁ ▁Grant ▁County ▁– ▁n ortheast ▁ ▁Si oux ▁County ▁– ▁east ▁ ▁Per kins ▁County , ▁South ▁Dak ota ▁– ▁south ▁ ▁Hard ing ▁County , ▁South ▁Dak ota ▁– ▁south west ▁ ▁Bow man ▁County ▁– ▁west ▁ ▁Slo pe ▁County ▁– ▁north west ▁ ▁Major ▁high ways ▁▁ ▁U . S . ▁Highway ▁ 1 2 ▁▁ ▁North ▁Dak ota ▁Highway ▁ 8 ▁▁ ▁North ▁Dak ota ▁Highway ▁ 2 2 ▁ ▁Prote cted ▁areas ▁ ▁North ▁Lem mon ▁Lake ▁State ▁Game ▁Management ▁Area ▁ ▁L akes ▁ ▁North ▁Lem mon ▁Lake ▁ ▁Mir ror ▁Lake ▁ ▁Dem ograph ics ▁▁ 2 0 0 0 ▁census ▁As ▁of ▁the ▁ 2 0 0 0 ▁United ▁States ▁Census ▁there ▁were ▁ 2 , 5 9 3 ▁people , ▁ 1 , 1 2 1 ▁households , ▁and ▁ 7 2 5 ▁families ▁in ▁the ▁county . ▁The ▁population ▁density ▁was ▁ 2 . 6