Multnomah Falls is by far the best known waterfall in the Columbia River Gorge. Much of this is due to its sheer size, at well over 600 ft it is the tallest waterfall in Oregon and one of the tallest year round waterfalls in the country. It also has its own freeway exit and a large visitors center at the base to accommodate the large number of visitors every day. While this site is almost always crowded, it's still definitely worth the stop just to appreciate the size of this amazing waterfall.