[19] The river flows southwest across the Sevier Desert, where it is used heavily for irrigation in the Delta area, and is dammed at the DMAD and Gunnison Bend reservoirs.

[22] This is underlain by marine sedimentary rock including thick limestone layers, which accumulated prior to the Jurassic when the western US was part of a shallow sea.

[27] The Sevier Desert was formed starting about 20 million years ago due to crustal stretching that lowered the local terrain.

[27] Another period of uplift occurred towards the end of the Tertiary, about 12–2 million years ago, creating most of the present-day mountain ranges and plateaus.

The dry Sevier Lake bed as well as deposits in the Redmond area, are a major source of salts, including halites and potassium sulfates.

[27] The largest sand dunes in Utah, found in Little Sahara Recreation Area, were formed from Sevier River delta deposits moved over thousands of years by prevailing winds.

[27] There have been relatively recent volcanic activity in the Sevier basin between 1000 and 1500 AD, when basalt flows occurred on the Markagunt and Paunsaugaut Plateaus and in Pahvant Valley.

Due to the semi-desert climate, the valleys of the Sevier River basin were historically mostly grassland and shrubland, with the seeds of Oryzopsis hymenoides (Indian ricegrass) being an important food source for Native Americans.

[30] Because the Sevier River provides some of the only water-based habitats in a large desert area, it is used by abundant migratory waterfowl, including geese, ducks, cranes, and shorebirds.

[30] Fur-bearing animals such as beaver and river otter were once widespread before being trapped out in the early 1800s, and predators such as kit foxes, coyotes, and cougars still roam less populated areas of the basin.

[27] Precipitation is sufficient to support many perennial streams and springs, which nourish mountain meadows and numerous small high elevation lakes.

Also once found in the area were the Rocky Mountain bighorn sheep, bison, grizzly bear and timberwolves which were all hunted to extinction in the 1800s or early 1900s.

[22] Paleo-Indians were present in southwestern Utah as early as 10,000 BC, when the climate was much wetter during the Pleistocene ice age and the Sevier basin was partially occupied by pluvial Lake Bonneville.

Wetlands along the shoreline and a much fuller Sevier River provided abundant habitat for fish and wildlife, supporting a larger human population.

[27] The ancestors of the Ute, Southern Paiute and Goshute peoples who populated the Sevier River basin immediately prior to European arrival migrated into the area possibly centuries after the decline of the Fremont culture.

[22] The first Europeans to see the river were the Spanish missionaries Francisco Atanasio Domínguez and Silvestre Vélez de Escalante who led the Domínguez–Escalante expedition of 1776, trying to find a way to Monterey, California from Santa Fe, New Mexico.

The expedition's cartographer, Don Bernardo Miera y Pacheco, sketched a map showing an outlet from Sevier Lake to the Pacific Ocean, which may have given rise to the myth of a Buenaventura River draining the Great Basin to the sea.

[27] The river was a major trade corridor during the late 18th and early 19th centuries, in no small part due to the route from Santa Fe opened up by Domínguez and Escalante.

[35] During the 1830s and 1840s the fur trade was in full force with thousands of beaver and otter taken from the Sevier River and its tributaries; most trappers were Native Americans although there were also many of British, French and Spanish origin.

[34] The slave trade also remained a major if controversial business and only ended after the Mexican–American War in 1848, after which the Sevier River became part of Utah Territory.

The first Mormon settlers arrived in the Sevier Valley in late 1849 under the direction of Brigham Young, but they and other whites passing through the region soon clashed with Native Americans.

[33] Sometime in early October 1853 a party of California-bound emigrants opened fire on a group of Pahvant Utes who had come to their camp to trade, killing one.

In retaliation, on October 26, 1853, the Pahvants attacked a railroad survey crew led by Captain John W. Gunnison, killing eight members of the party near what is now the town of Delta.

In one particularly dry year some residents in Millard County "were so angry they hired a posse in an unsuccessful attempt to remove upstream dams.

The 1,900 megawatt power station consumes two million tons of coal and draws 20,000 acre-feet (25,000,000 m3) of cooling water from the Sevier River each year.

Other boom towns of the period included Bullion City, Webster and Alunite, the latter of which produced significant quantities of aluminum ore.[50] Uranium was first discovered in Piute County in 1948.

[25] As annual precipitation tends to vary greatly up to 480,000 acre-feet (590,000,000 m3) of water can be stored in surface reservoirs, with the largest three – Sevier Bridge, Piute and Otter Creek – accounting for 75 percent of that capacity.

It is one of the longest man-made waterways in Utah, irrigating 20,000 acres (8,100 ha) along the western side of the valley in Sevier and Sanpete Counties.

[56] Parts of the Upper Sevier, and its higher tributaries and feeder lakes, are good trout waters, particularly in National Forest lands.

[59] Fishing is generally poor downstream of Marysvale Canyon due to the warm silty water, numerous diversion structures and degradation of riparian habitat.