It is positioned upon Interstate 81, in the Blue Ridge portion of the Southern Appalachian mountains in Southwest Virginia.

However, together with the neighborhoods, an additional 9,000 residents residing in unincorporated Smyth County have Marion mailing addresses, granting the Marion, VA ZIP code (24354) a total population of about 14,500, which is around half of the county's total population.

Marion, Virginia is the location of two large side-by-side ground storage water tower tanks, which are separately labeled "HOT" (in red letters) and "COLD" (in blue).

The landmarks, positioned just off of Marion exit 47, are visible to both north and south bound Interstate 81 traffic lanes.

According to the United States Census Bureau, the town has a total area of 5.2 square miles (10.7 km2), all of it land.

As of the 2020 United States Census, there were 6,022 people, 2,573 households, and 1,394 families residing within the town limits.

Back of the Dragon, a segment of SR16 popular among motorcycle and sports car enthusiasts for its sharp turns and scenic overlooks, begins in Marion, Virginia.

[14] In late September 2024, the town suffered from flooding and destruction from the impacts of Hurricane Helene.