The Mosby Shelter was located on the Appalachian Trail between Manassas Gap and Chester Gap in Northern Virginia. It was built in 1939 by the Civilian Conservation Corps, operating from their camp in Linden, Virginia, just north of the site of the shelter. Today, the location of the former shelter is called the "Mosby Campsite" and the nearby Tom Sealock Spring, which is one of the sources of the Rappahannock River.

The 1941 edition of the ATC's Guide to the Paths of the Blue Ridgeoffers this description of the shelter:

Mosby Lean-to is situated on the edge of a clearing on the crest of the long spur extending to the east from High Knob, about half way between Manassas and Chester Gaps. A small settlement that formerly was in this locality is said to have been called "Mosby" because several of Colonel Mosby's rangers resided nearby.

In 1980, the Mosby Shelter was stolen. Hikers arrived at the site to find that the shelter had been dismantled and removed, likely for the chestnut logs that had been used in its construction. It was not rebuilt.