It’s FREE! Hallelujah! But it’s packed on weekends. Good luck with finding parking between 11a and 3p.
The River has several waterfalls on the Oregon side. You can see 5 driving on US-30 or Historic Columbia River Highway Scenic Byway. To get there from Portland, on US-84E, exit for the Vista House at Crown Point, which is 20min east of Portland. There you get a great view of the Columbia River, a huge cousin of the great Mississippi River, but looks cleaner. FREE!
Next is Latourell Falls, if you can find parking. I gave up, so no pictures.
Next is Bridal Veil Falls, again if you can find parking. Again, no pictures.
Next is Wakeena Falls, which also has a small picnic area (maybe a campground, but I saw no tents) across from it. Parking is cuthroat.
Past Wakeena Falls, is Multnomah Falls, which is the one to see, if you had only time to see one. You can actually reach it from US-84E, there is an exit there for it’s own parking lot from I-84, and a short walk. The parking lot for I-84 might actually be bigger than the one on US-30. So if you only want to see the Multnomah Falls and nothing else, the interstate is probably the way to go and only 30min east of Portland. FREE!
Then past Multnomah Falls on US-30 (not the interstate), you see Horsetail Falls.
Once past the falls, you need to get back on the interstate. You can head back west to Portland, or head east and stop to see Bonneville Dam. There is a great display in the basement of the Army Corp of Engineers (yes, that’s correct, they have a visitor center for the dam) in the basement for seeing salmon (and a lot of pacific lampreys/eels) swiming upstream, from the fish stairs they built so they can get past the dam. You might actually be able to see them jumping the stairs too. And you get a great view of the dam and pass the locks that allow ships to pass through. FREE!
If you choose to keep going east, you can see the city of Hood River, an hour east of Portland. There in the summer, you can see para-sailing, and windsurfing on the Columbia River. You can also see the houses on the Washington State side of the river. What a great view, during the summer. Cost to rent equipment is unknown, but there are signs up that this is a day use fee area. LIKELY NOT FREE, BUT YOU GET TO DO MORE THAN LOOK AROUND.