Mount Jefferson is a stratovolcano in the Cascade Volcanic Arc, part of the Cascade Range, and is the second highest mountain in Oregon. It is situated in the far northeastern corner of Linn County on the Jefferson County line, with the lower reaches extending northward into southeastern Marion County. The mountain, about 105 miles (169 km) east of Corvallis, is in a rugged wilderness and is thus one of the hardest volcanoes to reach in the Cascades, though USFS Road 1044 does come within 4 miles (6.4 km) of the summit.