Zion National Park protects 229 square miles (about 590 km²) of canyon country in south-western Utah, next to the town of Springdale, where the Colorado Plateau meets the Great Basin and the Mojave Desert. Its centrepiece, Zion Canyon, is 15 miles (24 km) long and up to 2,640 ft (800 m) deep, cut by the North Fork of the Virgin River into the pale and red cliffs of the Navajo Sandstone, the remains of a Jurassic sand sea. The park's highest point is Horse Ranch Mountain at 2,660 m (8,726 ft) in the Kolob Canyons section, and its lowest is Coalpits Wash at 1,117 m (3,666 ft), a relief of about 1,600 m (5,100 ft). Proclaimed Mukuntuweap National Monument in 1909 and made Zion National Park on 19 November 1919, it received 4,984,525 visits in 2025.
Nine rock formations are exposed in the park, together recording about 150 million years of mostly Mesozoic sediment. Read from the canyon floor upward, they tell that story in order. Faults, lava and one fast river then turned the stack into the landscape visitors see.
Permian and Triassic seas: Kaibab Limestone to the Chinle Formation
The oldest rock in Zion is the Kaibab Limestone, laid down from about 260 million years ago as lime ooze in a warm, shallow arm of the ocean on the western edge of the supercontinent Pangaea, when Utah lay near the equator. Sponges lived on that sea floor, and their silica needles later recrystallised into bands of chert. The same yellowish-grey limestone forms the rim of the Grand Canyon to the south; in the park it appears in the Hurricane Cliffs above the Kolob Canyons Visitor Center and along Interstate 15. When the sea withdrew, the exposed limestone weathered into karst with channels up to 30 m (100 ft) deep.
Next came the Moenkopi Formation of the Early Triassic, up to 550 m (1,800 ft) thick, built from thousands of thin layers deposited as a coastline advanced and retreated: tidal flats, lagoons that left gypsum, river deltas and shallow sea. Ripple marks and mud cracks are preserved in its red shales. Its banded red, brown and pink beds form the buttes along State Route 9 between Virgin and Rockville. Above it lies the Late Triassic Chinle Formation, laid down by rivers and lakes and rich in volcanic ash, petrified wood and uranium minerals. Its base, the Shinarump conglomerate, makes cliffs up to 60 m (200 ft) high, and its Petrified Forest Member, about 110 m (350 ft) thick, is the same multicoloured layer exposed in Arizona's Petrified Forest. Purple Chinle slopes rise above Rockville.
The Early Jurassic Moenave and Kayenta formations finish the lower slopes. The Moenave's Springdale Sandstone, 23 to 46 m (75 to 150 ft) thick, was laid down by swifter, larger streams and holds fossils of large sturgeon-like freshwater fish, and the Moenave forms the low red cliffs seen from the Zion Human History Museum. The Kayenta, 61 to 183 m (200 to 600 ft) of river sand and silt, preserves sauropod footprints near the Left Fork of North Creek and makes the red and mauve slopes that run throughout Zion Canyon.
The Navajo Sandstone: a Jurassic erg 670 metres thick
By roughly 190 million years ago, mountains rising to the west had placed the region in a rain shadow, and about 150,000 square miles (388,000 km²) of western North America became a desert comparable to the modern Sahara. For perhaps 10 million years dunes piled up, reaching their greatest thickness, about 670 m (2,200 ft), at what is now the Temple of Sinawava in Zion Canyon. The grains are about 98 per cent rounded quartz, blown in from coastal dunes in what is now central Nevada.
This formation is the reason Zion looks the way it does. Its cliffs, including the West Temple, the Great White Throne and Angels Landing, are among the tallest sandstone walls in the world. The sloping laminations of ancient dune faces are visible everywhere, most strikingly on Checkerboard Mesa near the east entrance, where cross-bedding is cut by vertical cracks into a grid. The lower part of the Navajo is reddish from iron oxide that seeped down from the formation above; the upper part is pale tan to almost white. Because the sandstone is porous and its cement weak, it holds the region's main aquifer. Where water sinking through it meets the impermeable Kayenta below, it runs sideways and emerges in springs such as Weeping Rock, which seeps from the cliff above the canyon floor.
The desert did not last. In the Middle Jurassic, tidal flats carrying iron-rich mud laid down the Temple Cap Formation, which forms the capstone of the West Temple; rain washing its iron oxide down the cliffs leaves red streaks such as the one on the Altar of Sacrifice. A shallow inland sea then advanced from about 150 million years ago and deposited the Carmel Formation, a limestone 61 to 91 m (200 to 300 ft) thick that is best exposed on Horse Ranch Mountain. The youngest rock in the park, a small remnant of Cretaceous Dakota Sandstone about 30 m (100 ft) thick, caps that summit. It was laid down on the shore of the Western Interior Seaway, whose western coast then ran near Cedar City.
Hurricane Fault, Sevier Fault and 13 million years of uplift
As much as 850 m (2,800 ft) of Late Jurassic and Early Cretaceous rock may once have lain between the Carmel and the Dakota, and later formations were laid down on top of the Dakota, but none of it survives in Zion. The younger missing layers are probably the ones exposed further north-east in Bryce Canyon, whose oldest visible rock is the Dakota. Together, the Grand Canyon, Zion and Bryce form the Grand Staircase, a single sequence of strata stepping up from south to north.
Two kinds of tectonic force rearranged that stack. In the later Mesozoic, compression from subduction off the west coast, known as the Sevier Orogeny, folded and thrust the rock; in the Taylor Creek area of the Kolob section, slices of Moenave have been pushed over themselves along the Taylor Creek Thrust Fault. Then, about 20 to 25 million years ago, stretching of the crust that created the Basin and Range province to the west formed the two faults that bound the Markagunt Plateau beneath the park: the Sevier Fault on the east and the Hurricane Fault on the west. The Hurricane Fault is still active and runs at least 250 km (155 miles) from south of the Grand Canyon to Cedar City; at the park's southern boundary the rock on either side has been displaced by about 1,100 m (3,600 ft).
From 13 million years ago the whole Colorado Plateau rose, lifting the region by about 3,000 m (10,000 ft) and tilting the Markagunt Plateau gently east. That is why the oldest layers are exposed in Zion Canyon and the youngest in the Kolob Canyons. Uplift also steepened the streams. The Virgin River, and Taylor and La Verkin creeks in the Kolob section, began cutting down faster, following north-trending joints and faults in the rock, which is why the park's streams run in rectangular patterns.
Lava at Crater Hill and the lakes behind landslides
Volcanoes added the last rocks. Around 21 million years ago the Pine Valley laccolith, one of the largest intrusions of its type, formed to the west. From at least 1.4 million to about 250,000 years ago, basalt erupted intermittently along the Hurricane Fault; the oldest flows can be seen at Lava Point. About 100,000 years ago basalt from Crater Hill, the park's largest cinder cone, flowed into Coalpits and Scoggins washes and piled up more than 120 m (400 ft) deep in the ancestral Virgin River valley near the ghost town of Grafton. Water ponded behind the flows, forming Coalpits Lake and Lake Grafton, the largest of at least 14 lakes known to have formed in the park.
Most of the others were dammed by landslides. About 7,000 years ago the Sand Bench landslide blocked Zion Canyon just east of the Sentinel, and about 4,000 years ago the Sentinel Slide dammed the North Fork again, creating a lake that backed up to Weeping Rock. The present site of Zion Lodge sat under about 60 m (200 ft) of water for some 700 years, and the flat valley floor beside the scenic drive near the Sentinel Slide is that lake's legacy. Slides blocked the river again in 1923, 1941 and 1995, and on 2 September 1992 a magnitude 5.8 earthquake sent about 14 million cubic metres of rock sliding over weak Chinle claystone at Springdale, just outside the park entrance.
What the Virgin River carved: Zion Canyon, the Narrows and Kolob Arch
In all, about 1,800 m (6,000 ft) of rock has been stripped from above the Dakota Sandstone. The Virgin River does the work with one of the steepest gradients in North America, falling 9.5 to 15.2 m per km (50 to 80 ft per mile). In flood its water carries abrasive sand that scours the base of the cliffs until vertical slabs of jointed Navajo Sandstone shear away. In 1998 a flash flood raised the flow from about 6 to 125 m³ per second. The river has cut about 400 m (1,300 ft) in roughly 1 million years, a pace matching the Grand Canyon's fastest erosion; a million years ago Zion Canyon near the lodge was only half as deep, and only the upper half of the Great White Throne stood exposed.
Where uplift and downcutting outpace widening, the river leaves slot canyons. Above the Temple of Sinawava, where the 6-mile (9.7 km) Zion Canyon road ends, the Narrows close to just 6 m (20 ft) wide between walls up to 610 m (2,000 ft) tall. On the Kolob Terrace another slot, the Subway, cuts through the plateau, and in the Kolob Canyons section the same processes left Kolob Arch, whose span the Natural Arch and Bridge Society measured in 2006 at about 87.6 m (287 ft), among the longest natural arches in the world.
Geologists estimate the river can cut about another 300 m (1,000 ft) before it loses the gradient to carry sediment to the Colorado, and further uplift would extend that. The canyon is still being made. To follow the same layers up the Grand Staircase, read the guide to Bryce Canyon National Park, or see how Zion fits among the state's other plateaus, basins and ranges in Utah's landforms.