Plains . It is located at 36°24′2″N 97°52′51″W / 36.40056°N 97.88083°W / 36.40056; -97.88083 (36.400583, -97.880784) [ 19 ] , 70 miles (110 km) North of Oklahoma City . According to the United States Census Bureau , the city has a total area of 74.1 square miles (192 km 2 ), of which 74.0