The land that now forms Boone and several other Iowa counties was ceded by the Sac and Fox nation to the United States in a treaty signed on October 11, 1842. On January 13, 1846, the legislative body of the Indiana Territory authorized creation of twelve counties in the Iowa Territory, with general descriptions of their boundaries. Boone County's name referred to Captain Nathan Boone, son of Daniel Boone, an American pioneer who formed the Wilderness Trail and founded the settlement of Boonesborough, Kentucky. County residents selected Boonesboro as the county seat in 1851. The first building erected in the new settlement was a double log house, to be used as interim county office and courthouse. It was supplemented by a two–story building erected in 1856, then replaced by a three-story building in 1868. The nearby settlement of Montana was incorporated in 1866, when a railway station was built there. It was renamed to Boone in 1871. It continued to grow, and it annexed the settlement of Boonesboro in 1887, thus becoming the county seat. After the second courthouse became too small for the county's expanding populace, a new building replaced it. It was completed in 1917.
Geography
According to the U.S. Census Bureau, the county has a total area of, of which is land and is water.
U.S. Route 169 – runs south from Webster County through the west-central portion of Boone County. At its intersection with US 30, U.S. 169 runs east three miles to Ogden, then runs south to Dallas County.
Iowa Highway 17 – runs south through eastern Boone County to Jordan, west one mile, then south to the boundary line between Dallas and Polk counties.
Iowa Highway 144 – runs across the southwest tip of the county from northwest to southeast.
Iowa Highway 210 – enters south line of county at Woodward, then runs east and east-northeast across the southern portion of county to Story County.
The 2010 census recorded a population of 26,306 in the county, with a population density of. There were 11,756 housing units, of which 10,728 were occupied.
2000 census
As of the census of 2000, there were 26,224 people, 10,374 households, and 7,137 families residing in the county. The population density was 46 people per square mile. There were 10,968 housing units at an average density of 19 per square mile. The racial makeup of the county was 98.53% White, 0.36% Black or African American, 0.20% Native American, 0.22% Asian, 0.26% from other races, and 0.43% from two or more races. 0.83% of the population were Hispanic or Latino of any race. There were 10,374 households out of which 31.20% had children under the age of 18 living with them, 58.00% were married couplesliving together, 7.80% had a female householder with no husband present, and 31.20% were non-families. 26.70% of all households were made up of individuals and 11.80% had someone living alone who was 65 years of age or older. The average household size was 2.44 and the average family size was 2.95. In the county, the population was spread out with 24.80% under the age of 18, 8.40% from 18 to 24, 27.10% from 25 to 44, 23.30% from 45 to 64, and 16.40% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 95.90 males. For every 100 females age 18 and over, there were 91.70 males. The median income for a household in the county was $40,763, and the median income for a family was $49,346. Males had a median income of $32,504 versus $23,838 for females. The per capita income for the county was $19,943. About 4.50% of families and 7.60% of the population were below the poverty line, including 8.00% of those under age 18 and 5.90% of those age 65 or over.
The population ranking of the following table is based on the 2010 census of Boone County. †county seat
Rank
City/Town/etc.
Municipal type
Population
1
†Boone
City
12,661
2
Madrid
City
2,543
3
Ogden
City
2,044
4
Sheldahl
City
319
5
Boxholm
City
195
6
Pilot Mound
City
173
7
Luther
City
122
8
Fraser
City
102
9
Beaver
City
48
10
Berkley
City
32
Politics
Prior to 1932, Boone County was primarily Republican in presidential elections, aside from 1912 when the county backed Bull Moose candidate & former Republican President Theodore Roosevelt. From 1932 to 1980, the county was a swing county, voting for the national winner in all elections in that period aside from 1960. From 1984 to 2012, the county was consistently Democratic in presidential elections, but swung hard in 2016 by 20.7 points to back Republican Donald Trump similar to many other counties in Iowa.