Portland Arch Nature Preserve
A little less than a 3-hour drive from Chicago, outside a small town of Attica, IN is a tucked-away natural wonder known as the Portland Arch. It is named for a natural bridge formation carved by a tributary of the Wabash River.
The approach to this nature preserve could not be more unassuming. A small country road delivers you to a crossing where a few modest dwellings are scattered, and a plain brown painted sign points left to “Portland Arch NP”.
The relatively short but quite rugged wooded trail follows a dramatic sandstone gorge and meandering creek. As you descend a moss-covered wooden straicase toward the stream bed, cool mist from the running water offers welcome relief on a muggy day, and voices of children splashing below echo off the carved walls of the gorge. The path is muddy and slippery from recent rains. After crossing a small wooden bridge, a few dozen steps over the curving path around the sandstone wall bring you face to face with a massive natural bridge, the swelled creek rushing through the tunnel opening at its base. Unlike the natural arch formations in Kentucky, or out west, with their soaring columns and dramatic openings, this one is heavy, mysterious and imposing, and passing through, you feel like you’re sneaking around the feet of an enormous sleeping animal.
The deeply etched walls of the gorge are covered with cascading colonies of cliff-dwelling plants, giving the place a verdant and damp look of some prehistoric canyon. The torrential rains that passed through a day or two before have caused small waterfalls to form here and there, adding to the drama, and the otherworldly atmosphere at the bottom of the gorge.
As you climb back up, the trail dries somewhat, and the dense, moist vegetation is replaced by stands of trees including beech, basswood, sugar maple, and black walnut. Along the canyon's upper edge is a mix of white pines and oaks with native wildflowers growing in their shade.
Summary
Bear Creek flows through a deep ravine with high rock walls. It is joined by a small tributary stream that has carved an opening through a massive Mansfield sandstone formation and created a natural bridge known as Portland Arch.
Portland Arch has been recognized for its uniqueness since the first settlers came to western Indiana. A resort and then a Boy Scout camp were located in this area in the past. Now Portland Arch is a National Natural Landmark, as well as a nature preserve.
More information form Indiana DNR here.