Middlebourne is a town in Tyler County, West Virginia, United States. The population was 870 at the 2000 census. It is the county seat of Tyler County. The town was established by an enactment of the Virginia General Assembly in 1813. Two explanations have been given for the name of the town: One is that it was located halfway between Pennsylvania and a series of salt wells along the Kanawha River upstream of Charleston; the other is that it is located midway between the source and the mouth of Middle Island Creek, which flows through the town.
There were 370 households out of which 30.0% had children under the age of 18 living with them, 51.9% were married couples living together, 11.9% had a female householder with no husband present, and 33.2% were non-families. 31.4% of all households were made up of individuals and 16.8% had someone living alone who was 65 years of age or older. The average household size was 2.31 and the average family size was 2.89.
In the town the population was spread out with 23.3% under the age of 18, 7.5% from 18 to 24, 25.1% from 25 to 44, 28.7% from 45 to 64, and 15.4% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 85.1 males. For every 100 females age 18 and over, there were 80.3 males.
The median income for a household in the town was $128,704, and the median income for a family was $40,893. Males had a median income of $35,000 versus $19,167 for females. The per capita income for the town was $14,673. About 12.6% of families and 13.9% of the population were below the poverty line, including 18.3% of those under age 18 and 11.9% of those age 65 or over.