The Octonia Stone, also known as Octoney, Octeny, Octona, and Octuna Stone, is a historic boundary marker located near Stanardsville, Greene County, Virginia. The stone marks the terminus of the westernmost boundary line of the 24,000-acre Octonia Grant. It is a granite-type rock which is part of a natural outcropping in a hayfield. The stone is engraved with a figure 8, composed of two, nearly perfect circles, with a cross touching the top of the 8.

Correct coordinates are: (38.3337176, -78.4536142) - msw 11Nov2021

It was listed on the National Register of Historic Places in 1970.