The county was formed in 1859 from the eastern part of Ashe County, North Carolina. It was named for the Allegheny River. Numerous boundary adjustments have been made since it was established, but none have resulted in new counties.Townships:
The county is divided into seven townships: Cherry Lane, Cranberry, Gap Civil, Glade Creek, Piney Creek, Prathers Creek, and Whitehead.
Prominent Residents
* Robert L. Doughton: Bob Doughton (1863-1954) was a powerful United States Congressman from Alleghany County from 1911-1953. From 1933-1947 he was the Chairman of the influential House Ways and Means Committee. He used his influence as Chairman to create the Blue Ridge Parkway, which runs along the county's eastern and southern borders. Doughton Park, the largest and most popular park on the Parkway, is named in his honor. He also played a major role in the passage of the Social Security Act. His former home is currently a popular bed-and-breakfast in Alleghany County.
* Rufus A. Doughton: Born in 1857, he was the older brother of Robert Doughton. A prominent politician in his own right, he served as the Speaker of the North Carolina House of Representatives, and was North Carolina's Lieutenant Governor from 1893-1897. He died in 1946.
* Zach Galifianakis (born 1969), a popular stand-up comedian and actor, lives on a farm near Sparta, the county seat. He splits his time between the farm and his work in New York City.
