Jerome is a town in the Black Hills of Yavapai County in the U.S. state of Arizona. Founded in the late 19th century on Cleopatra Hill overlooking the Verde Valley, Jerome is roughly north of Phoenix along State Route 89A between Sedona and Prescott. Supported in its heyday by rich copper mines, it was home to more than 10,000 people in the 1920s. As of the 2020 census, its population was 464.
The town owes its existence mainly to two ore bodies that formed about 1.75 billion years ago along a ring fault in the caldera of an undersea volcano. Tectonic plate movements, plate collisions, uplift, deposition, erosion, and other geologic processes eventually exposed the tip of one of the ore bodies and pushed the other close to the surface, both near Jerome. In the late 19th century, the United Verde Mine, developed by William A. Clark, extracted ore bearing copper, gold, silver, and other metals from the larger of the two. The United Verde Extension UVX Mine, owned by James Douglas Jr., depended on the other huge deposit. In total, the copper deposits discovered in Jerome's vicinity were among the richest ever found.
Jerome made news in 1917 when labor unrest involving the Industrial Workers of the World (IWW) led to the expulsion at gunpoint of about 60 IWW members, who were loaded on a cattle car and shipped west. Production at the mines, always subject to fluctuations, boomed during World War I, fell thereafter, rose again, then fell again during and after the Great Depression. As the ore deposits ran out, the mines closed for good in 1953, and the population dwindled to fewer than 100. Efforts to save the town from oblivion succeeded when residents turned to tourism and retail sales. Jerome became a National Historic Landmark in 1967. By the early 21st century, it had art galleries, coffeehouses, restaurants, a state park, and a local museum devoted to mining history.
Geography Jerome is about north of Phoenix and southwest of Flagstaff along Arizona State Route 89A between Sedona to the east and Prescottto the west. The town is in Arizona's Black Hills, which trend north–south. The town lies within the Prescott National Forest at an elevation of more than . Woodchute Wilderness is about west of Jerome, and Mingus Mountain, at above sea level, is about south of town. Jerome State Historic Park is in the town itself. Bitter Creek, a tributary of the Verde River, flows intermittently through Jerome. East of Jerome at the base of the hills are the Verde Valley and the communities of Clarkdale and Cottonwood, site of the nearest airport.
Geology
Most of Cleopatra Hill, the rock formation upon which Jerome was built, is 1.75 billion years old. Created by a massive caldera eruption in Precambrian—elsewhere more narrowly identified as Proterozoic—seas south of what later became northern Arizona, the Cleopatra tuff was then part of a small tectonic plate that was moving toward the proto-North American continent. After the eruption, cold sea water entered Earth's crust through cracks caused by the eruption. Heated by rising magma to or more, the water was forced upward again, chemically altering the rocks it encountered and becoming rich in dissolved minerals. When the hot solution emerged from a hydrothermal vent at the bottom of the ocean, its dissolved minerals solidified and fell to the sea floor. The accumulating sulfide deposits from two such vents formed the ore bodies, the United Verde and the UVX, most important to Jerome 1.75billion years later.
These ore bodies formed in different places along a ring fault in the caldera. About 50million years after they were deposited, the tectonic plate of which they were a part collided with another small plate and then with the proto-North American continent. The collisions, which welded the plates to the continent, folded the Cleopatra tuff in such a way that the two ore bodies ended up on opposite sides of a fold called the Jerome anticline.
No record exists for the next 1.2billion years of Jerome's geologic history. Evidence from the Grand Canyon, further north in Arizona, suggests that thick layers of sediment may have been laid down atop the ore bodies and later eroded away. The gap in the rock record has been called the Great Unconformity.
About 525 million years ago, when northern Arizona was at the bottom of a shallow sea, a thin layer of sediment called the Tapeats Sandstone was deposited over the Cleopatra tuff. Limestones and other sediments accumulated above the sandstone until about 70million years ago, when the Laramide Orogeny created new mountains and new faults in the region. One of these faults, the Verde Fault, runs directly under Jerome along the Jerome anticline. Crustal stretching beginning about 15million years ago created Basin and Range topography in central and southern Arizona, caused volcanic activity near Jerome, and induced movement along the Verde Fault. This movement exposed the tip of the United Verde ore body at one place on Cleopatra Hill and moved the UVX ore body to below the surface. Basalt, laid down between 15 and 10million years ago, covers the surface beneath the UVX headframes and Jerome State Historic Park. The basalt, the top layer of the Hickey Formation, caps layers of sedimentary rock.
The natural rock features in and around Jerome were greatly altered by mining. The town is underlain by of mine shafts. These may have contributed to the subsidence that destroyed some of Jerome's buildings, which slid slowly downhill during the first half of the 20th century. The United Verde open pit, about deep, is on the edge of town next to Cleopatra Hill. The side of the pit consists of gabbro from the Precambrian. Mine shafts beneath the pit extend to below the surface.
Attempts to control erosion on Jerome's steep hillsides by planting Ailanthus altissima has caused new problems. This invasive species, commonly known as "tree of heaven" or "paradise tree", has roots that emit poisons that kill native trees and shrubs. The roots can damage sewer lines and septic tanks, and the tree can sprout through asphalt and sidewalks and into structures. In 2015, the Jerome Fire Department hosted workshops on how to control the trees, which are difficult to eradicate.
History Early The Hohokam were the first people known to have lived and farmed near Jerome from 700 to 1125 CE. Later, long before the arrival of Europeans, other native peoples likely mined the United Verde ore body for the colorful, copper-bearing minerals malachite and azurite. The top of the ore body was accessible because it was visible on the surface.
The first Europeans to arrive in the area were the Spanish conquistadors. At the time, the area was part of "New Mexico", and the Spaniards often organized silver- and gold-prospecting expeditions in the area. In 1585, Spanish explorers made note of the ore, but did not mine it because their government had sent them to find gold and silver, not copper.
19th century The area became part of Mexico when Mexico gained its independence from Spain in 1821, and part of the United States by terms of the 1848 Treaty of Guadalupe Hidalgo, which concluded the Mexican–American War. The war's major consequence was the Mexican Cession of the northern territories of Alta California and Santa Fe de Nuevo México to the United States.
Angus McKinnon and Morris A. Ruffner filed the first copper-mining claims at this location in 1876. In 1880, Frederick A. Tritle, the governor of the Arizona Territory, and Frederick F. Thomas, a mining engineer from San Francisco, bought these claims from the original owners. In 1883, with the aid of eastern financiers, including James A. MacDonald and Eugene Jerome of New York City, they created the United Verde Copper Company. The small, adjacent mining camp on Cleopatra Hill was named Jerome in honor of Eugene Jerome, who became the company secretary. United Verde built a small smelter at Jerome and constructed wagon roads from it to Prescott, the Verde Valley, and the Atlantic and Pacific Railroad depot at Ash Fork. However, transport by wagon was expensive, and in late 1884 after the price of copper had fallen by 50%, the company ceased all operations at the site.
Four years later, William A. Clark, who had made a fortune in mining and commercial ventures in Montana, bought the United Verde properties, and among other improvements, enlarged the smelter. He ordered construction of a narrow-gauge railway, the United Verde and Pacific, to Jerome Junction, a railway transfer point to the west. As mining of the ore expanded, Jerome's population grew from 250 in 1890 to more than 2,500 by 1900. By then, the United Verde Mine had become the leading copper producer in the Arizona Territory, employing about 800 men, and was one of the largest mines in the world. Over its 77-year life (1876 to 1953), this mine produced nearly 33million tons of copper, gold, silver, lead and zinc ore. The metals produced by United Verde and UVX, the other big mine in Jerome, were said to be worth more than $1billion. According to geologists Lon Abbott and Terri Cook, the combined copper deposits of Jerome were among the richest ever found.
Jerome had a post office by 1883. It added a schoolhouse in 1884 and a public library in 1889. After four major fires between 1894 and 1898 destroyed much of the business district and half of the community's homes, Jerome was incorporated as a town in 1899. Incorporation made possible the collection of taxes to build a formal fire-fighting system and to establish building codes that prohibited tents and other fire hazards within the town limits. Local merchant and rancher William Munds was the first mayor.
By 1900, Jerome had churches, fraternal organizations, and a downtown with brick buildings, telephone service, and electric lights. Among the thriving businesses were those associated with alcohol, gambling, and prostitution serving a population that was 78% male. In 1903, New York's The Sun proclaimed Jerome "the wickedest town in the West".
20th century Jerome, which was legally separate from United Verde and supported many independent businesses, did not meet the definition of a company town, though it depended for decades largely on a single company. In 1914, a separate company, the United Verde Extension Mining Company (UVX), led by James S. Douglas, Jr. (nicknamed Rawhide Jimmy), discovered a second ore body near Jerome that produced a bonanza. The UVX Mine, also known as the Little Daisy Mine, became spectacularly profitable; during 1916 alone, it produced $10million worth of copper, silver, and gold, of which $7.4million were profit. This mine eventually produced more than $125million worth of ore and paid more than $50million in dividends. Total production amounted to four million tons, much less than the United Verde total, but from uncommonly rich ore averaging more than 10% copper and in places rising to 45%.