how deep is the columbia river

The Columbia River is generally a moderately deep river, with most commonly traveled sections under 100 feet deep, but its very deepest spots can reach around 350 feet in dam-created reservoirs.

Quick Scoop

• In many urban areas like Portland, Oregon, the Columbia River is typically about 20–40 feet deep, with some pockets dropping to around 75 feet.

• Through much of the Columbia River Gorge, most of the channel is about 25–45 feet deep, with the deepest parts of the Gorge reaching roughly 90 feet.

• The deepest commonly cited section in the United States is in Franklin D. Roosevelt Lake, the reservoir behind Grand Coulee Dam, where depths reach about 350 feet.

• For commercial shipping, the maintained navigation channel from the river’s mouth up toward Portland is kept around 40–43 feet deep, allowing large cargo vessels to pass safely.

A bit of “wow” context

Geologists estimate that during the massive Ice Age Missoula Floods, temporary floodwaters rushing through parts of the Columbia valley may have been hundreds of feet deep—over modern Portland, flood depths are estimated around 400 feet, and near Wallula Gap up to about 1,000 feet—far greater than the river’s present everyday depths.

So if you’re picturing the Columbia today, think mostly 20–90 feet in many river reaches, with a few man‑made reservoir sections plunging to roughly 350 feet at their deepest.

TL;DR: The Columbia River is usually a few dozen feet deep in most places, but in its deepest reservoir sections it drops to about 350 feet.

Information gathered from public forums or data available on the internet and portrayed here.