Coal Vein Trail

Overview

This short interpretive loop is the park’s geology class you actually want to take. The outer loop is 0.8 miles total (with a 0.6-mile inner option), just 26 feet of gain, and usually takes 30–45 minutes at a relaxed pace. Expect an easy walk with a few brief steeper bits and stairs. It’s not the most dramatic view hike in the South Unit, but it’s one of the most informative.

Wayfinding and logistics

Start to the left from the trailhead to follow the numbered posts in order. Grab the trail brochure in advance or in the NPS app—signage can be sparse, and the guide is what turns the posts into a story. There’s a small lot at the trailhead and it’s often uncrowded; recent visitors report no restrooms here. Keep your eyes on the path for cactus near the margins.

What you’ll see

You’ll walk through layers that tell roughly 60 million years of badlands history: soft gray bentonite clays, the black stripe of a coal seam, and red, baked “clinker” formed when burning coal heated the overlying sediments. A coal seam here reportedly burned for decades in the mid-20th century, leaving slumps where the coal vanished underground and a cap of clinker that now resists erosion. In season, look for wildflowers among prickly pear, juniper, and sage. Wildlife is possible in the area—give anything on hooves or paws plenty of space.

Conditions and tips

This loop is fully exposed—sun and heat are the main challenges. Bring water and sun protection and avoid midafternoon in summer. Bentonite turns slick when wet; if it’s rained recently, expect mud and careful footing. The numbered posts and brochure make the experience; without them, many find the loop underwhelming. If you’re chasing big vistas, pair this with another short hike nearby for a more varied day.

Best time to hike

Go early or late for cooler temps and softer light on the rock layers. Spring and fall are the sweet spots; summer afternoons can be punishing. Weekdays are typically quiet. Windy days are common—another reason to favor morning or evening.

Regulations and etiquette

Stay on established paths to protect fragile badlands soils and keep back from steep edges. All natural and cultural features are protected—don’t disturb or remove anything. Maintain at least 25 yards from wildlife, yield to horseback riders, keep noise low, and pack out all trash. Pets, bicycles, and motorized equipment aren’t allowed on park trails.