Economic prosperity, built on this farming base, followed Davis County into the twentieth century. By 1910 the county sported two gristmills, two nurseries, eight irrigation companies, and six canning factories. Five years later it also had a sugar factory. A great variety of crops, fruit, and livestock was raised. New schoolhouses, chapels, stores, and other structures popped up on the landscape. Three railroads served the county's transportation needs. During and immediately after World War II, significant changes began to appear in Davis County. Farming, while still important, began to lose its position as the economic leader. Defense installations in the Clearfield-Layton area, such as Hill Air Force Base
and the Naval Supply Depot, began to employ large numbers of people. When the navy depot closed, industry and related enterprises purchased the buildings in 1963 and developed the site into the Freeport Center, a bustling manufacturing and distribution center. Suburbs to meet housing needs developed around the Freeport-Hill hub and also in the southern part of the county for people who commuted to Salt Lake City
. Service industries, to support this growing population, started to become prominent in the county's economic makeup.
Although the state's smallest county in size, Davis is one of the fastest growing in population. The number of residents doubled between 1940 and 1950, doubled again by 1960, doubled again by 1975, and is expected to double again by 1995. It is presently Utah's third most populous county.