An early milestone in the settlement of Duvall proper was the relocation of the town of Cherry Valley around 1909, when the Chicago, Milwaukee and St. Paul Railroad agreed to move Cherry Valley homes and businesses to Duvall in order to continue the construction of a railroad line along the Snoqualmie River.. The newly-relocated town, briefly named Cosgrove after Samuel G. Cosgrove) underwent a real estate boom: streets and sidewalks were laid and a train depot was constructed. It was followed by a movie house, a drug store. a new schoolhouse, and several hotels.. By 1911, the Duvall Citizen began publishing.
There were 1,596 households out of which 49.4% had children under the age of 18 living with them, 71.4% were married couples living together, 7.1% had a female householder with no husband present, and 18.1% were non-families. 13.2% of all households were made up of individuals and 2.5% had someone living alone who was 65 years of age or older. The average household size was 2.88 and the average family size was 3.15.
In the city the population was spread out with 32.4% under the age of 18, 5.0% from 18 to 24, 42.9% from 25 to 44, 16.5% from 45 to 64, and 3.2% who were 65 years of age or older. The median age was 33 years. For every 100 females there were 98.0 males. For every 100 females age 18 and over, there were 99.9 males.
The median income for a household in the city was $71,300, and the median income for a family was $78,740. Males had a median income of $51,164 versus $41,806 for females. The per capita income for the city was $27,764. About 2.8% of families and 3.8% of the population were below the poverty line, including 5.2% of those under age 18 and none of those age 65 or over.
Over the last ten years, certain aspects of the event have been banned each year. An example of this would be potato guns and silly string, both now officially banned from sale by vendors during the event. Although some aspects have been banned over the years the event continues to grow in popularity.