Where the Virgin River comes from

About 162 miles from the high plateaus of southern Utah to Lake Mead, by way of Zion, St. George, a corner of Arizona and the Nevada desert.

Two forks off the Markagunt Plateau

The Virgin starts on the Markagunt Plateau, the high, forested tableland north and east of Zion that tops out over 11,000 feet near Brian Head and Cedar Breaks. Snowmelt and summer storms on the plateau feed two forks that run south through Zion country and join near Springdale to form the main river.

North Fork

The North Fork begins at Cascade Falls, where an underground stream pours out of the Pink Cliffs just north of Zion National Park. From there it gathers side streams across the plateau, drops into Zion through the Narrows, and runs the length of Zion Canyon to Springdale. The uppermost gauge on the map sits at the bottom of the Narrows.

East Fork

The East Fork rises in Long Valley near Long Valley Junction and runs south past Glendale, Orderville and Mount Carmel Junction, then turns west into Parunuweap Canyon, a deep, little-visited gorge along the southern edge of the park. It meets the North Fork just south of Springdale.

Navajo Lake and Cascade Falls

Navajo Lake sits high on the plateau at about 9,000 feet. It formed when a lava flow blocked the valley, cutting off the natural surface drainage of Duck Creek, a headwater of the Sevier River. So the lake has no surface outlet. It drains down, through sinkholes in the limestone of the Claron Formation at its eastern end.

One lake, two destinations. In 1954–55 the U.S. Geological Survey poured dye into the sinks. It came out in two places:

Cascade Spring (Cascade Falls) after about 8½ hours. This water feeds the North Fork of the Virgin, then the Colorado River.
Duck Creek Spring after about 53 hours. This water goes to the Sevier River, which never reaches the sea; it ends in the Great Basin.

Roughly 40% of the water entering the sinks went to Cascade Spring and about 60% to Duck Creek Spring.

The route to Cascade Falls is a cave system roughly a mile long, dissolved out of the Claron Formation, running from the southeastern end of the lake to the face of the Pink Cliffs. A small earthen dike now holds the main lake back from the sinks. In wet years the lake overtops it, more water reaches the cave, and Cascade Falls runs hard. In dry years the falls can shrink to a trickle.

The short Cascade Falls trail starts off the Navajo Lake road (off Utah 14 east of Cedar City) and ends on a platform where you can watch the river come out of the rock.

The river, top to bottom

Cascade Falls & Long ValleyThe North and East Forks start on the Markagunt Plateau.
Zion Narrows & Parunuweap CanyonEach fork cuts its own slot canyon through Zion's sandstone.
SpringdaleThe forks join to form the main Virgin River.
Rockville, Virgin & La VerkinNorth Creek, then LaVerkin Creek and Ash Creek come in.
Hurricane & Quail CreekWater is diverted to Quail Creek and Sand Hollow reservoirs.
St. GeorgeThe Santa Clara River joins; Fort Pearce Wash comes in from the south.
Virgin River GorgeThe river leaves Utah through a canyon in the northwest corner of Arizona, beside I-15.
Littlefield & MesquiteBeaver Dam Wash joins; the river crosses into Nevada.
Overton Arm, Lake MeadThe Muddy River joins and the Virgin ends in Lake Mead, where it once met the Colorado.

Main tributaries

Stream	Where it joins	Notes
North Creek	Near Virgin	Drains the west side of Zion; the Subway is on its Left Fork.
LaVerkin Creek	La Verkin	Drains the Kolob Canyons section of Zion.
Ash Creek	Near La Verkin	Comes down from the Pine Valley Mountains and New Harmony.
Quail Creek	Near Hurricane	Small creek, mostly known for Quail Creek Reservoir, which is filled by a diversion from the Virgin.
Santa Clara River	St. George	Rises in the Pine Valley Mountains and passes Gunlock and Ivins.
Fort Pearce Wash	Below St. George	Dry most of the year; can run big after storms on the Arizona Strip.
Beaver Dam Wash	Littlefield, AZ	Long desert wash from the Utah–Nevada border country.
Muddy River	Overton Arm, NV	Spring-fed river from the Moapa Valley.

Why it matters for floods

Snowmelt from the Markagunt Plateau brings the Virgin its spring high water. Its sudden floods come from summer monsoon cloudbursts, often over slickrock side canyons that have no gauges. A storm over the upper North Fork or the East Fork can send a surge down through Zion and on to St. George hours later. That travel time is what the live map estimates.