Blennerhassett Island is an island on the Ohio River below the mouth of the Little Kanawha River, near Parkersburg in Wood County, West Virginia, United States.

Nemacolin, chief of the Delaware Nation, made it his last home, dying in 1767.

European Americans knew it as Backus Island, named for Elijah Backus, who purchased it in 1792 in the wave of westward settlement following the American Revolutionary War.

In 1798, Harman Blennerhassett, a figure in the Aaron Burr "treason" conspiracy, purchased the east end of the island with his wife Margaret Agnew and it became known by their name.

This article about a location in Wood County, West Virginia is a stub.