Wikipedia served as the source for the population information. Note that the population increased between 1910 and 1920.

Britt is located in Hancock County, which was established on January 15, 1851. It was named for John Hancock (1737-1793), who served as the President of the First Continental Congress. The county seat was located variously at Amsterdam, and then Hancock Center, and then Concord. In 1898, Britt attempted to win the county seat, but the move was countered by the city of and then Concord where a brick Courthouse was built in 1868. In 1898, Britt attempted to win the county seat from Concord, but the move was countered by the city of Garner. Although the cornerstone was laid for the Hancock County Courthouse on June 8, 1899, Britt continued to contest the location until an election was held in March of 1903. Garner won the election, and Britt finally conceded.

(Source: Pratt, LeRoy G. “The Counties and Courthouses of Iowa.” Mason City, Ia; Klipto Printing & Office Supply Company, 1977, p. 143-146.)