According to the U.S. Census Bureau, the county has a total area of, of which is land and is water. Roaring River State Park is located in the southern part of the county, amid the Mark Twain National Forest.
As of the census of 2000, there were 34,010 people, 13,398 households, and 9,579 families residing in the county. The population density was 44 people per square mile. There were 15,964 housing units at an average density of 20 per square mile. The racial makeup of the county was 94.09% White, 0.11% Black or African American, 0.86% Native American, 0.27% Asian, 0.03% Pacific Islander, 3.25% from other races, and 1.38% from two or more races. Approximately 5.04% of the population were Hispanic or Latino of any race. 26.5% were of American, 15.5% German, 11.7% English and 10.4% Irish ancestry. There were 13,398 households out of which 31.20% had children under the age of 18 living with them, 59.30% were married couplesliving together, 8.40% had a female householder with no husband present, and 28.50% were non-families. 24.70% of all households were made up of individuals and 11.60% had someone living alone who was 65 years of age or older. The average household size was 2.51 and the average family size was 2.98. In the county, the population was spread out with 26.10% under the age of 18, 7.80% from 18 to 24, 26.10% from 25 to 44, 23.90% from 45 to 64, and 16.10% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 98.30 males. For every 100 females age 18 and over, there were 95.60 males. The median income for a household in the county was $28,906, and the median income for a family was $34,043. Males had a median income of $25,381 versus $18,631 for females. The per capita income for the county was $14,980. About 11.80% of families and 16.60% of the population were below the poverty line, including 23.50% of those under age 18 and 11.90% of those age 65 or over.
All of Barry County is a part of Missouri’s 158th Legislative District in the Missouri House of Representatives and is represented by . All of Barry County is a part of Missouri’s 29th District in the Missouri Senate and is currently represented by .
Texas State Senator Ted Cruz received more votes, a total of 3,189, than any candidate from either party in Barry County during the 2016 presidential primary election.
Voters in Barry County from both political parties supported candidates who finished in second place in the state at large and nationally.
Former Governor Mike Huckabee received more votes, a total of 2,396, than any candidate from either party in Barry County during the 2008 presidential primary.
