The second tallest mountain in the U.S. state of Oregon after Mount Hood, Mount Jefferson lies within Jefferson, Linn, and Marion counties, in the central part of the state. Reaching an elevation of , the volcano has a proximal relief of . It is not usually visible from the city of Portland, though it is visible on clear days from Salem and can be noticed from highways to both the east and the west of the Cascade Range. The average elevation of the terrain around Jefferson is , meaning that Jefferson's cone rises nearly above its surroundings.