The Promontory Mountains are a

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

Box Elder County, Utah Box Elder County is a county at the northwestern corner of Utah, United States. As of 2018, the estimated population is 54,950. Its county seat and largest city is Brigham City. The county was named for the box elder trees that abound in the co ...

. The range is oriented north–south and has a length of about . The southern portion forms a

cape A cape is a clothing accessory or a sleeveless outer garment which drapes the wearer's back, arms, and chest, and connects at the neck. History Capes were common in medieval Europe, especially when combined with a hood in the chaperon. Th ...

extending south into the

Great Salt Lake The Great Salt Lake is the largest saltwater lake in the Western Hemisphere and the eighth-largest terminal lake in the world. It lies in the northern part of the U.S. state of Utah and has a substantial impact upon the local climate, particula ...

. The

First transcontinental railroad North America's first transcontinental railroad (known originally as the "Pacific Railroad" and later as the " Overland Route") was a continuous railroad line constructed between 1863 and 1869 that connected the existing eastern U.S. rail netwo ...

was completed with the

Golden Spike The golden spike (also known as The Last Spike) is the ceremonial 17.6-karat gold final spike driven by Leland Stanford to join the rails of the first transcontinental railroad across the United States connecting the Central Pacific Railroad ...

just north of the range at

Promontory Summit Promontory is an area of high ground in Box Elder County, Utah, United States, 32 mi (51 km) west of Brigham City and 66 mi (106 km) northwest of Salt Lake City. Rising to an elevation of 4,902 feet (1,494 m) above sea ...

in the

Utah Territory The Territory of Utah was an organized incorporated territory of the United States that existed from September 9, 1850, until January 4, 1896, when the final extent of the territory was admitted to the Union as the State of Utah, the 45th state. ...

. Today, trains cross the Promontory Point at the southern tip of the range via the

Lucin Cutoff The Lucin Cutoff is a railroad line in Utah, United States that runs from Ogden to its namesake in Lucin. The most prominent feature of the cutoff was a railroad trestle crossing the Great Salt Lake, which was in use from 1904 until the late ...

railroad Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a pre ...

causeway A causeway is a track, road or railway on the upper point of an embankment across "a low, or wet place, or piece of water". It can be constructed of earth, masonry, wood, or concrete. One of the earliest known wooden causeways is the Sweet Tra ...

across the lake. Great Salt Lake Map

Geology

The Promontory Mountains are a

block fault Fault blocks are very large blocks of rock, sometimes hundreds of kilometres in extent, created by tectonic and localized stresses in Earth's crust. Large areas of bedrock are broken up into blocks by faults. Blocks are characterized by rela ...

range typical of the

Basin and Range Province The Basin and Range Province is a vast physiographic region covering much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating ...

. The west side of the range is bounded by the East Great Salt Lake

normal fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

which passes under the lake along the west side of

Antelope Island Antelope Island, with an area of 42 square miles (109 km2), is the largest of ten islands located within the Great Salt Lake in the US state of Utah. The island lies in the southeastern portion of the lake, near Salt Lake City and Davis Cou ...

and on to the south shore of the lake to the west side of the

Oquirrh Mountains The Oquirrh Mountains is a mountain range that runs north-south for approximately 30 miles (50 km) to form the west side of Utah's Salt Lake Valley, separating it from Tooele Valley. The range runs from northwestern Utah County–centr ...

where it continues on

strike Strike may refer to: People * Strike (surname) Physical confrontation or removal *Strike (attack), attack with an inanimate object or a part of the human body intended to cause harm *Airstrike, military strike by air forces on either a suspected ...

as the Oquirrh Fault. The East Antelope Island fault runs from the east side of Antelope Island to the north beneath the lake to the east side of the Promentaries where it continues as the East Promontory Mountains fault zone. These two fault systems parallel the larger

Wasatch Fault The Wasatch Fault is an active fault located primarily on the western edge of the Wasatch Mountains in the U.S. states of Utah and Idaho. The fault is about long, stretching from southern Idaho, through northern Utah, before terminating in cen ...

which runs to the east of Great Salt Lake. The faults are normal faults which dip to the west.W. Adolph Yonkee, et al., ROAD AND TRAIL LOGS OF ANTELOPE ISLAND STATE PARK, DAVIS COUNTY, UTAH, Fig. 2 in Geologic Road, Trail, and Lake Guides to Utah's Parks and Monuments 2000 Utah Geological Association Publication 29
/ref>

History

The Promontory Mountains of were bypassed by the

(north)NPS Historical Handbook for Golden Spike National Historic Site
/ref> and the replacement 1904

trestle through Promontory Point (south), which was replaced by a 1959

.Lucin Cutoff Railroad Trestle, After the Trestle
/ref>

References

External links

* {{Geographic Location , Northwest = , North = Northern Promontory Mountains &

Promontory Summit, Utah Promontory is an area of high ground in Box Elder County, Utah, United States, 32 mi (51 km) west of Brigham City and 66 mi (106 km) northwest of Salt Lake City. Rising to an elevation of 4,902 feet (1,494 m) above sea ...

, Northeast= Blue Spring Hills , West =

, Centre = Promontory Mountains , East = Bear River Bay , Southwest = Great Salt Lake , South = Promontory Point
Great Salt Lake,
Fremont and

s farther beyond,

even farther , Southeast = Great Salt Lake Mountain ranges of Box Elder County, Utah Mountain ranges of Utah