At the start of the 20th century the western edge of Crook County experienced fits and starts of many a township—Bend and Redmond took root, while Opal City, Deschutes, and others became footnotes. Irrigation canals brought water and dreams of blooming deserts. With the arrival of the railroad in 1911, the population exploded. Two super-mills take root on the banks of the Deschutes: Brooks-Scanlon and Shelvin-Hixon. Libraries existed in Bend and Redmond as largely volunteer-led efforts, struggling to find permanent homes. In 1916, voters established Deschutes County in a break from Crook County and Prineville to better control their own destinies. Among the accomplishments of the young county was the foundation of the Deschutes County Library system in January 1920, with 3,488 books in circulation and 1,252 cardholders by the end of that first year. The new system took over the Bend and Redmond libraries and over the next few years established drop off stations in La Pine, Sisters, Terrebonne, Lower Bridge, Tumalo, and even served the mobile logging camp communities of Brooks-Scanlon and Shevlin-Hixon.

In 1920, the county population reached 9,622 with more than 5,600 residents living in Bend. The decade was about permanence: wooden store fronts gave way to brick and mortar buildings, market roads wound their way through small farms and dairies, and schools opened already overcrowded. By the end of the decade, two-story brick high schools stood poised along the downtown districts of Bend (1925) and Redmond (1922), ready to raise the first generation of Deschutes County graduates. Small city fairs merged into the first county fair in 1920 and the Deschutes County Fairgrounds was constructed in Redmond. In 1921, the first city roads were paved. The mills continued to expand, in 1921 and 1923. The Bend library branch, still without a permanent home, was gifted land along Wall Street in 1924. Construction of a building took another 14 years.

Events of the 1920s shaped the demographics of Central Oregon, too. American Nationalism swept the country post WWI. The mills encouraged naturalization for all immigrant employees with a goal of 100% citizenship. Nationalism also brought the Ku Klux Klan to Central Oregon. Established in 1921, the Bend Chapter of the KKK had an office on Greenwood. In 1923, the Klan burned a cross on Pilot Butte. Immigration to Central Oregon included large numbers of Irish and Eastern European Catholics, and their influence on regional development included the establishment of St. Charles Hospital in 1922 after Father Luke Sheehan invited the Sisters of St. Joseph to come to Bend to help with growing medical care needs. The KKK’s opposition to Catholicism found no foothold in Bend and the chapter disintegrated almost as soon as it began.