The city sits near the source of the Willamette River, which stretches 150 miles north, from the Calapooya Mountains outside of town to its mouth on the Columbia. Carving its way between mountains, the Cascade Range to the east and the Oregon Coast Range to the west, the river defines a fertile valley where tens of thousands of years ago a series of ice age floods surged southwest from Lake Missoula, traveling over eastern Washington and bringing with their floodwaters rich soil and volcanic rock that now shore up the layers of its earth, alluvial plains fit for a vast variety of agriculture.
