Olson Mountain is an extinct shield volcano in southern Oregon's Jackson County, south of Prospect and northeast of Medford. Its greatest significance is its connection to Upper and Lower Table Rock, the two well-known plateaus north of Medford. Lava flows from eruptions of Olson Mountain formed those features. Over time, the Rogue River carved into the surrounding landscape and eroded the rock, leaving the lava elevated above the terrain. That erosion also contributed to the collapse that helped create the distinctive Table Rocks as they appear today.