The highway also traverses through a wildlife refuge and marsh near milepost 154. At milepost 146, I-35 enters Logan County. Often, the exits are numbered according to the nearest milepost, known as the mile-log system. The new 23-lane toll gate is near milepost 2.4. The zero milepost was later placed to mark that spot. This chaining system differs from the milepost or mileage system. They hid in ambush in the wadi of Milepost 105. Vehicles commonly drive as far as the airstrip and buildings located at Milepost 222. Just before Osier at Milepost 320, the track crosses Cascade Trestle.