Blennerhassett Island's history stretches back to ca. 9000 B.C when Native Americans settled on its shores. Around 1770, white squatters moved into the area, taking rights to the island and establishing the first white settlement in the 1790s. The Blennerhassett family built a beautiful mansion on the island from 1798-1800. It was the largest and most magnificent private residence in the Mid-Ohio Valley until it burned in 1811. Blennerhassett Island gained permanent national fame in 1805-1806 when it became the base of operations for the famous Aaron Burr "Conspiracy." Today, it continues to be one of the Ohio River's most famous islands, and in 1978, the Island became a West Virginia state park. From 1984-1991, the state of West Virginia rebuilt the Blennerhassett Mansion.
Many Mid-Ohio Valley residents have volunteered their time for the Blennerhassett project through three organizations: the Blennerhassett Island Historical Park Commission, the Blennerhassett Historical Foundation, Inc., and the Friends of Blennerhassett. The Blennerhassett Island Historical State Park Commission was established in 1972 as a public corporation within the executive branch of the state government. When the Island went into the state parks system in 1989, the Commission became an advisory body to the state on all matters relating to the development and maintenance of theBlennerhassett State Park. The Blennerhassett Historical Foundation, Inc. was formed in 1982 to provide financial and resource support to the development and operation of the Park. The Friends of Blennerhassett is a committee of the Foundation which provides the working core of volunteer support for the Park. Established in 1984, the Friends staff the gift shops in the Blennerhassett Museum and on the island and provide docents who offer guided tours of theBlennerhassett Mansion.