The Willamette River gorge is situated in the northwestern part of the Oregon State of the United States and the valley is the most crowded region in the state. The gorge is bounded by mountain ranges to the west, east, and south. The floor of the gorge is wide, even and fertile due to floods at the end of the previous glacial epoch.
The Willamette River gorge is situated centrally within the huge alluvial-deposited soils of the drainage basin of the Willamette River. It spreads far away from the banks of the river to both the west and east barrier ranges. The southern end of the gorge is close to the meeting point of its Coast and Middle forks close to Eugene, and its northern end is at the mouth of the Willamette River on the Columbia River, Portland. The Branch Rivers and the waterways of the gorge were of great significance for water transportation in the growth of the Oregon Territory and the Oregon State pending well past the influx of modern highways and roads.
The Willamette River gorge embraces several of the major cities of the Oregon State. The majority of the citizens of the state reside within the basin, where one or more huge ice-age floods left the floor of the gorge thick with flood-carried residues, making the gorge extremely fertile. An extraordinarily prolific agricultural area, the gorge was extensively publicized as a promised land of the flowing honey and milk sort from the 1820s. Later, it became the destination of option at Oregon City for the oxen-drawn trains of organized migrants, traveling west on the dangerous and coarse 2,900 km to 3,400 km (1,800 to 2,100 miles) of pathway beds of the Oregon Trail during the 1840s to 1880s.
Much of the fertility of the Willamette valley is based on a succession of huge ice-age torrents that came from the Montana State’s Lake Missoula and scoured across the Eastern Washington, sweeping its earth along the Columbia River Gorge. When floodwaters met up log-and-ice jams at the Kalama City in the southwestern part of Washington, the floodwater caused a support that crammed the whole Willamette Valley to a depth that ranges from 300 feet to 400 feet (91 m to 122 m) above the existing sea level. A few geologists propose that the Willamette River gorge flooded in this way numerous times at the time of the previous ice age.
If the floodwaters of that scale covered Portland at a height of 20 feet (6.1 meters) in 2010, only the crowns of the Mount Tabor, West Hills, Rocky Butte, Mount Scott and Kelley Butte would able to be seen, such as only some of the tallest skyscrapers of the city. The heights for other cities in the Willamette River gorge include Oregon City at a height of 138 feet (42 meters), Newberg at a height of 175 feet (53 meters), McMinnville at a height of 157 feet (48 meters), Corvallis at a height of 235 feet (72 meters), Salem at a height of 154 feet (47 meters), and Eugene at a height of 430 feet (130 meters). The lake slowly drained away, leaving the covered sedimentary soils on the floor of the valley to a height ranging from 180 feet to 200 feet (55 m to 61 m) above the existing sea level all through the Yamhill, Tualatin, and Willamette valleys.