Polk, founded in 1906 and named after U.S. President James K. Polk, was the last town established in Polk County. When the Union Pacific Railroad began building a branch line in the area, J. Wesley Wilson, his brothers Nathan and Victor, and brother-in-law C. C. McCune, formed the City Improvement Company to obtain land and lay out the town.
After a townsite had been surveyed, the company held a public sale of lots on September 11, 1906, which attracted more than 1,000 prospective buyers. A whirlwind of building activity followed, and the village boomed. Houses and stores from nearby Arborville and Stark were moved to Polk to take advantage of the railroad.
By 1907 four passenger and two freight trains arrived daily. The village grew to include four churches, five grocery stores, three banks, two hotels, a livery barn, blacksmith, school, and newspaper. By 1914 water and electric systems had been installed. The town's peak population of 561 was reached in 1920. Agriculture was and still remains the mainstay of the area, and the village continues as a trade center for the surrounding region.