According to the U.S. Census Bureau, the county has a total area of 1,156 square miles (2,995 km²), of which, 1,151 square miles (2,980 km²) of it is land and 6 square miles (14 km²) of it (0.48%) is water. A large number of streams drain the county including Elk Creek and Salt Creek.
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As of the census<1> of 2000, there were 18,804 people, 6,097 households, and 4,578 families residing in the county. The population density was 16 people per square mile (6/km²). There were 6,774 housing units at an average density of 6 per square mile (2/km²). The racial makeup of the county was 64.29% White, 0.55% Black or African American, 2.33% Native American, 1.21% Asian, 0.39% Pacific Islander, 26.68% from other races, and 4.54% from two or more races. 46.54% of the population were Hispanic or Latino of any race. 8.5% were of German, 5.6% English, 5.5% American and 5.4% Irish ancestry according to Census 2000. 58.7% spoke English and 40.4% Spanish as their first language.
There were 6,097 households out of which 41.4% had children under the age of 18 living with them, 59.6% were married couples living together, 9.6% had a female householder with no husband present, and 24.9% were non-families. 21.5% of all households were made up of individuals and 10.1% had someone living alone who was 65 years of age or older. The average household size was 3.01 and the average family size was 3.51.
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The median income for a household in the county was $35,062, and the median income for a family was $40,138. Males had a median income of $32,210 versus $21,521 for females. The per capita income for the county was $14,730. About 13.0% of families and 16.1% of the population were below the poverty line, including 19.5% of those under age 18 and 8.2% of those age 65 or over.
http://en.wikipedia.org/wiki/Colusa_County,_CaliforniaStrongly Republican, of course.