According to the U.S. Census Bureau, the county has an area of, of which is land and is water.
Major highways
U.S. Route 20 – runs east–west across central Webster County, through Moorland and Coalville.
U.S. Route 169 – enters northern Webster County at mid-county and runs south to Harcourt. It runs four miles east, then turns south to exit the county.
Iowa Highway 7 – enters western Webster County running east from Manson. It runs east to its terminus at US Highway 169 at Fort Dodge.
Iowa Highway 175 – enters southeastern Webster County, running west from Stratford. It runs west and south–north to its connection to US Highway 169, four miles east of Harcourt.
Iowa Highway 144 – enters southern Webster County near its midpoint. It runs north to its connection to Iowa Highway 175, three miles west of Harcourt.
The 2010 census recorded a population of 38,013 in the county, with a population density of. There were 17,035 housing units, of which 15,580 were occupied.
2000 census
As of the census of 2000, there were 40,235 people, 15,878 households, and 10,304 families in the county. The population density was 56 people per square mile. There were 16,969 housing units at an average density of 24 per square mile. The racial makeup of the county was 93.39% White, 3.39% Black or African American, 0.30% Native American, 0.66% Asian, 0.02% Pacific Islander, 1.10% from other races, and 1.15% from two or more races. 2.35% of the population were Hispanic or Latino of any race. Of the 15,878 households 30.20% had children under the age of 18 living with them, 51.80% were married couplesliving together, 9.50% had a female householder with no husband present, and 35.10% were non-families. 30.30% of households were one person and 13.10% were one person aged 65 or older. The average household size was 2.38 and the average family size was 2.97. The age distribution was 24.50% under the age of 18, 11.10% from 18 to 24, 25.50% from 25 to 44, 21.60% from 45 to 64, and 17.40% 65 or older. The median age was 38 years. For every 100 females there were 100.30 males. For every 100 females age 18 and over, there were 98.20 males. The median household income was $35,334 and the median family income was $43,772. Males had a median income of $31,047 versus $23,042 for females. The per capita income for the county was $17,857. About 6.70% of families and 10.00% of the population were below the poverty line, including 12.30% of those under age 18 and 7.00% of those age 65 or over.
Communities
Cities
Badger
Barnum
Callender
Clare
Dayton
Duncombe
Fort Dodge
Gowrie
Harcourt
Lehigh
Moorland
Otho
Stratford
Vincent
Census-designated place
Coalville
Unincorporated communities
Burnside
Lanyon
Townships
Badger
Burnside
Clay
Colfax
Cooper
Dayton
Deer Creek
Douglas
Elkhorn
Fulton
Gowrie
Hardin
Jackson
Johnson
Lost Grove
Newark
Otho
Pleasant Valley
Roland
Sumner
Wahkonsa
Washington
Webster
Yell
Population ranking
The population ranking of the following table is based on the 2010 census of Webster County. †county seat
In recent presidential elections, Webster County had a strong Democratic lean, voting for the party's candidate in every election from 1984 to 2012. In 2016 however, the county swung hard to vote for Republican Donald Trump by a wide margin, a nearly 27 point swing compared to 2012.
