Decatur County is one of about 3,141 counties and county equivalents in the United States. It has 372.6 sq. miles in land area and a population density of 67.1 per square mile. In the last three decades of the 1900s its population grew by 8.0%. On the 2000 census form, 99.5% of the population reported only one race, with <0.1% of these reporting African-American. The population of this county is 0.5% Hispanic (of any race). The average household size is 2.58 persons compared to an average family size of 3.03 persons. In 2008 manufacturing was the largest of 20 major sectors. It had an average wage per job of $43,402. Per capita income grew by 4.5% between 1997 and 2007 (adjusted for inflation).

People & Income Overview (By Place of Residence)	Value	Rank in U.S.	Industry Overview (2008) (By Place of Work)	Value	Rank in U.S.
Population (2008)	24,998	1588	Covered Employment	12,287	1272
Growth (%) since 1990	5.7%	1857	Avg wage per job	$34,419	968
Households (2000)	9,389	1562	Manufacturing - % all jobs in County	38.7%	66
Labor Force (persons) (2008)	12,452	1558	Avg wage per job	$43,402	924
Unemployment Rate (2008)	6.4	1049	Transportation & Warehousing - % all jobs in County	3.0%	1115
Per Capita Personal Income (2007)	$30,050	1305	Avg wage per job	$40,222	1221
Median Household Income (2007)	$45,711	923	Health Care, Social Assist. - % all jobs in County	4.6%	1886
Poverty Rate (2007)	10.0	2514	Avg wage per job	$26,587	1603
H.S. Diploma or More - % of Adults 25+ (2000)	79.1	1,576	Finance and Insurance - % all jobs in County	2.2%	1832
Bachelor's Deg. or More - % of Adults 25+ (2000)	11.5	2,275	Avg wage per job	$48,814	466