Address: Historic Columbia River Hwy, Cascade Locks, OR 97014
To get to the Horsetail falls from Multnomah is simple. Both are located on the Historic Columbia River Highway, with Horsetail east of Multnomah. To get there depends on your location. If you were fortunate enough to park at the base of Multnomah, simply drive down the road east. If you parked in the lot, get back on the 84 highway and get off at the immediate next exit, backtracking until you reach the falls.
Horsetail falls is...skippable. Easily.
At the same time, it's also really convenient to add to your intinerary for the day because the falls can be enjoyed within 1-5 minutes. The falls is right next to the road and all you need to do is park, take a picture, and continue on. Well, I mean most excursions happen in that order, but what I mean to say is that, because the falls is so small, you can experience it quickly. Thus, if you absolutely have to cut something out during your trip to the area, Horsetail Falls would be top of the list of falls you can skip.
To make the spot more challenge, you can also continue hiking up towards PonyTail Falls. The trailhead to the waterfall is right next to Horsetail.