In the early 1900s, Jerome was a booming mining town of nearly 15,000; after commercial mining ended in 1953, its population fell to roughly 400

Most towns lose population slowly, gradually, over time. Jerome lost virtually everyone within a matter of decades, and the reason comes down to a single mineral. The small mountain town practically disappeared because of the mineral mined in the mountain it was built on. According to the Arizona Memory Project, Jerome's population peaked at nearly 15,000 and dropped to roughly 400 today. That single statistic captures the arc of this little mining town built into the side of Cleopatra Hill.

A copper discovery that turned a hillside into a city

Jerome could not have developed gradually. It happened suddenly when a mining company discovered one of the largest copper deposits in the United States and hired thousands of workers to extract it right away. The United Verde Mine laid the groundwork for future development when it opened in Jerome in the 1880s. According to the Arizona Geological Survey, the mine’s ore came from a huge sulfide deposit on the ancient ocean floor, and it produced copper, gold, silver, and manganese. Hardworking people traveled from across the country to Jerome for jobs as copper prices rose rapidly to meet demand for electrical wiring and equipment. By the end of the 1920s, Jerome had become a fully functional city with hotels, a hospital, saloons, and a business district at the foot of the slope where the mine was located. Therefore, housing and business developed there because the mine was necessary for the city’s existence.

The blasting that made the town itself unstable

Jerome's location was never easy to build on, and mining made it worse. Blasting below ground to loosen the copper ore, along with the vast tunnels carved beneath the town, caused parts of Jerome to shift down the hillside literally. According to the Arizona Memory Project's account of the town's postal history, the local jail slid down the hill about 300 feet before coming to rest on its side, and the post office building on Hull Street was deemed unfit for use because the ground kept shifting. Miners and their families continued to work and live in Jerome because the jobs were there and so was the ore.

When copper prices fell, so did the population

Copper prices were volatile, and Jerome's economy had no alternative. When the Great Depression began, copper prices plummeted, and by 1939 the smaller United Verde Extension mining operation had been terminated, according to the same postal history record. The larger United Verde Mine held on for a while, but lower ore grades and a diminished demand eventually caught up to it as well. Commercial mining in Jerome ceased in 1953, and the population followed quickly. Families who had come for work left when the work did, since little else kept them in Jerome. Within just a few years of the 1953 shutdown, the population had collapsed from close to 15,000 to as few as 50 to 100 residents, small enough that outsiders began referring to Jerome as a ghost town.

How roughly 400 residents kept Jerome from disappearing

A small town could have been easily abandoned, and it almost happened. A few things convinced Jerome's residents to stay and make the best of it. First, the federal government designated Jerome a National Historic Landmark District in 1966. The town was recognized for its significance as an example of American industrial heritage tied to the copper mining era that shaped the area in the early-to-mid 20th century. This designation appears to have strongly motivated preserving the buildings in Jerome rather than abandoning them, and it also helped turn the entire town into a historical experience. Second, Jerome residents were persistent in their efforts to maintain the town's services. For instance, when the US Post Office decided to close Jerome's post office in 1975 because it was too expensive to maintain, residents protested and persuaded officials to reverse the decision, according to the Arizona Memory Project. These efforts, combined with a gradual repopulation by artists and a growing tourism economy from the 1960s onward, brought the town's population back up to roughly today's 400 residents, a modern recovery distinct from the near-total abandonment of the 1950s. Jerome remains an incorporated town today.

The risk Jerome exposed for towns built on one industry

The town itself did not cause Jerome's rise and fall. Copper caused it. A community built around a single mine can struggle when that industry declines. The same pattern can affect other mining towns. The same risk affects any town or region dependent on a single industry, whether it's mining, a particular type of manufacturing, or even a single employer. If that industry leaves, people will tend to leave as well unless something else replaces it.