A:
The Columbia River Gorge is a National Scenic Area that encompasses parts of both Washington and Oregon, and covers a large distance from east to west. The most scenic part is along Interstate 84 east of Portland, Oregon, although there are some places in Washington that impress. Depending upon traffic in Portland, and how far into the Gorge you want to go, it is about a 30 minute to one hour drive to most destinations on the Oregon side. As for "the" waterfall, that is a bit of a confusing question, since there are about 77 waterfalls in this area. Swimming "on" a waterfall is an unusual way to express it. I gather that you wish to stand at the bottom of one, in the falls itself. This is not advised for most of the falls here. Most are not accessible in that way, and most are quite powerful. And most are icy cold. I do not recall any falls that has a rep for people standing in them. But...a few areas near falls are popular swimming areas and one trail, the Oneonta Gorge Trail, actually goes up a creek to a waterfall. Eagle Creek has a nice swimming area near Punchbowl Falls. But...a lot of the trails are still closed due to the fire damage in 2017. Check locally to be sure the one you want is open at the time you wish to visit. Friends of the Gorge has a website that keeps up to date with trail access. (This website does not allow links.) Fishing is popular on the Columbia River during the salmon run. By waterfalls, there isn't much to fish for here. Most of the local lakes are well stocked though. One last thing you might wish to do. Open Google Earth and type in "Columbia Gorge." By perusing it you will get a better idea of what to expect.