Black Canyon of the Gunnison National Park

Lore & Background

The canyon’s name comes from the fact that parts of the gorge receive only 33 minutes of sunlight each day, which causes the rocky walls to appear black. The Gunnison River drops an average of 34 feet per mile through the park’s 12-mile section, making it the fifth steepest mountain descent in North America; at Chasm View the drop reaches 240 feet per mile. At its narrowest point the canyon is just 40 feet wide at the river. The extreme steepness and depth resulted from several geologic processes acting together. The Precambrian gneiss and schist that form most of the steep walls originated 1.7 billion years ago during a metamorphic period caused by the collision of ancient volcanic island arcs with the southern end of present-day Wyoming. Lighter-colored pegmatite dikes crosscut these basement rocks. The area was uplifted during the Laramide orogeny between 70 and 40 million years ago, and later volcanism from the West Elk, La Sal, Henry, and Abajo mountains buried the region in thousands of feet of ash and debris. The modern Gunnison River set its course 15 million years ago, and a broad uplift 2 to 3 million years ago caused the river to cut through softer volcanic deposits until it reached the extremely hard metamorphic rocks. The river carved through these at a rate of one inch every 100 years, creating the steep walls seen today. The Ute people knew the canyon long before Europeans, calling the river “much rocks, big water” and avoiding it out of superstition. Captain John Williams Gunnison provided the first official account in 1853, describing the country as the roughest he had ever seen. After his death later that year, the river was renamed the Gunnison River in his honor.

Reader's Guide

Black Canyon of the Gunnison National Park preserves one of the most dramatic and inaccessible sections of the Gunnison River canyon. Its significance lies in its unique combination of depth, sheerness, narrowness, and darkness, which distinguishes it from other canyons of the American West. The park's geology records over 1.7 billion years of Earth's history, from Precambrian metamorphism to Quaternary river incision. The canyon's extreme steepness, caused by the river cutting through hard Precambrian rock at a rapid rate, creates walls that are nearly vertical in many places. The park also holds historical importance as the site of a remarkable 1880s railroad engineering feat by the Denver and Rio Grande Railroad, which built a narrow-gauge line through the canyon. Though the route later lost importance after an alternate route through Glenwood Springs was completed, the canyon remains a testament to both natural forces and human determination.

Did You Know?

• Parts of the gorge only receive 33 minutes of sunlight a day.
• The Gunnison River drops an average of 34 feet per mile through the park's 12-mile section.
• At its narrowest point the canyon is only 40 ft wide at the river.

A Billion-Year Story Carved in Stone

The gneiss and schist that form the majority of the steep canyon walls date back roughly 1.7 billion years, born from a metamorphic event triggered when ancient volcanic island arcs collided with the southern edge of what is now Wyoming. Lighter pegmatite dikes, visible crosscutting those basement rocks, crystallized later in the same Precambrian window. Far more recently, the Laramide orogeny between 70 and 40 million years ago lifted this ancient bedrock as part of the broader Gunnison Uplift. Volcanic episodes during the Tertiary period then buried the region under thousands of feet of ash and debris contributed by the West Elk, La Sal, Henry, and Abajo mountain ranges. The modern Gunnison River locked in its westward path about 15 million years ago, first slicing through the softer volcanic layers. A broad uplift two to three million years ago forced the river downward until it struck the impossibly hard Precambrian rock. Unable to reroute, it ground through the gneiss at roughly one inch per century, and that combination of extreme rock hardness and relentless downward cutting is what produced the sheer, near-vertical walls visible today.

The Steepest Descent in North America

Few waterways in the continent match the Gunnison River's relentless plunge. Across the full 48-mile length of the canyon, the river loses an average of 34 feet per mile, a gradient that ranks it as the fifth steepest mountain descent in North America. For perspective, the Colorado River drops just 7.5 feet per mile as it threads through the Grand Canyon. Within the national park boundaries alone, the steepest stretch occurs at Chasm View, where the river sheds a staggering 240 feet per mile. The park encompasses 12 miles of the river's total course and holds what is widely regarded as the deepest, most dramatic segment of the gorge; the canyon extends upstream into Curecanti National Recreation Area and downstream into the Gunnison Gorge National Conservation Area. The extreme steepness means sunlight barely penetrates the depths—parts of the gorge receive only 33 minutes of direct sun per day. At its tightest pinch the canyon narrows to just 40 feet of water at the river. Author Duane Vandenbusche captured the effect: no other Western canyon combines depth, sheerness, narrowness, darkness, and dread quite like this one.

From Ute Superstition to National Monument

Long before any European set eyes on the gorge, the Ute people knew the canyon existed. They called the river "much rocks, big water" and, according to the historical record, deliberately avoided the canyon out of superstition. By the time the United States declared independence in 1776, two Spanish expeditions had already passed the canyons, and throughout the 1800s fur trappers searching for beaver pelts likely encountered the area, though none left a written account. The first official description came in 1853 from Captain John Williams Gunnison, who was surveying a potential route between Saint Louis and San Francisco. He called the surrounding country "the roughest, most hilly and most cut up" he had ever seen and skirted the canyon southward toward present-day Montrose. Tragically, Gunnison was killed by the Ute later that same year, and the river he had named the Grand was subsequently renamed in his honor. The gorge was designated a national monument on March 2, 1933, and on October 21, 1999, it was redesignated a national park, absorbing 4,000 acres previously held by the Bureau of Land Management while the adjacent Gunnison Gorge National Conservation Area was created simultaneously.

Rail Through the Impossible

When William Jackson Palmer's Denver and Rio Grande Railroad pushed its line from Denver toward Gunnison in 1881, the goal was to connect the region to the booming gold and silver mines of the San Juan Mountains. The terrain, however, made standard 4-foot-8½-inch rail impossible, so Palmer opted for a narrower three-foot gauge. Irish and Italian laborers then spent more than a year carving a 15-mile roadbed between Sapinero and Cimarron, a job that cost a staggering $165,000 per mile. The final mile alone reportedly cost more than the entire Royal Gorge project had required. On August 13, 1882, the first passenger train threaded through the Black Canyon. The editor of the Gunnison Review-Press rode in one of the observation cars and declared the canyon "undoubtedly the largest and most rugged" he had ever witnessed. The park today offers two primary entrances: the south rim gate sits 15 miles east of Montrose, while the north rim gate, 11 miles south of Crawford, shuts down for the winter months.