Every September, Humboldt still holds the Labor Day parade it started in 1907. The old smelter town of Humboldt is printed on this map, along with Mortimer Farms, Blue Hills Farms, the Dewey-Humboldt Town Hall, the Dewey-Humboldt Town Library, the Kate Garber Memorial Community Center, Humboldt Elementary School and the Agua Fria Christian Church. The Agua Fria River, Round Hill and Fain Tank are printed too.
Dewey-Humboldt is in Yavapai County, in the Agua Fria River valley 15 miles east of Prescott.
KNOWOL made this map in 2026 and gave it the look of an old atlas. The shaded relief of Round Hill comes from United States Geological Survey elevation data, and the streets were drawn from Census Bureau files. The town was incorporated on December 20, 2004, from two neighboring communities, Dewey and Humboldt, and it had 3,894 people at the 2010 census. The Agua Fria, Spanish for “cold water,” is a 120-mile intermittent stream. It rises northeast of Granite Dells and flows south through Black Canyon to Lake Pleasant and on toward the Gila River.
A ranch to feed the miners
Gold turned up on Lynx Creek in the spring of 1863, and that summer the rancher and prospector King Woolsey settled the Dewey area and founded the Agua Fria Ranch to supply the miners, in what was then called Woolsey Valley. He dug an irrigation system off the river, brought in some of the first cattle in the newly organized Yavapai County and built a small quartz mill and a water-powered grist mill at the falls of the Agua Fria, where Humboldt is now. He later went bankrupt and sold the ranch to the Bowers brothers, who kept farming it and supplied the region with corn and barley. The ruins of the ranch house are on the National Register and can still be seen from the Old Black Canyon Highway.
As more ranches and farms filled the valley, a post office and stage station named Agua Fria opened in 1875 on the wagon road from Prescott to Phoenix. Its isolation ended in 1898, when the Prescott and Eastern Railroad came up the Agua Fria with sidings at Cherry Creek and at Val Verde, where a smelting company built a large plant. When a new post office opened that year, the community took the name Dewey, probably for Admiral Dewey’s victory at Manila in the Spanish-American War.
Click to explore a larger preview. The digital watermark does not appear on printed maps.
Humboldt and the smelter
In the early 1900s the Consolidated Arizona Smelting Company built a giant smelter at Val Verde that served mines across the Arizona Territory, and in 1905 the post office was renamed Humboldt for Baron Alexander von Humboldt, who had visited New Spain and predicted greater riches to the north. With two trains a day the town boomed, and by 1907 it had 1,000 people. To show off its growth, it held a Labor Day celebration that year with a parade on Main Street. The parade became an annual tradition, and the Agua Fria Chamber of Commerce now holds it on the last Saturday in September.
The town rose and fell with the mines. The nearby Iron King Mine became the most productive mine in the Bradshaws and produced $100 million in gold, silver, lead and zinc before it closed in 1968. The railroad track came out in 1971. Many of Humboldt’s historic buildings date from the early twentieth century, and a lone smelter smokestack still stands over them on Main Street.
Pumpkins and sweet corn
Part of the old Woolsey ranch land became Young’s Farm in 1946, a family farm that sold turkeys and pumpkins and drew visitors from around Arizona to its hay rides and its October Pumpkin Fest. Farming in the area ended in 2006, when the last working farm was sold, and Young’s Farm closed late that year. In April 2011 Mortimer Family Farms bought the old Young’s farm, and it sells sweet corn in summer and pumpkins in fall. Today Dewey is a low-density residential area.
This Dewey-Humboldt map is a good addition to an office, library or den, and it can help teach children the geography and history of the area. It’s made for anyone who calls Dewey-Humboldt home, from Main Street in Humboldt to Mortimer Farms, and KNOWOL created it in 2026 to show the town as it looks today. Zoom in on the preview above to explore the details, then click here to get your copy of the Dewey-Humboldt map.
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