Fort Valley is a mountain valley in Shenandoah County, Virginia. The so-called "valley within a valley" lies between the two arms of the northern Massanutten Mountain range in the Shenandoah Valley. The valley is closed at its southern end, and is constricted and nearly closed to the north, where Passage Creek flows through a narrow gap. The valley opens out toward the center, becoming about three miles (4.8 km) wide at its widest. In all, Fort Valley is 23 miles (37 km) long.
Fort Valley is mostly rural, consisting of private farmland, surrounded by the George Washington National Forest (GWNF), which covers the slopes on both the east and west mountains. The Elizabeth Furnace and Camp Roosevelt Recreation Area of the GWNF are located within Fort Valley.
Roads exit the valley at its northern end (S.R. 678) between Strasburg and Front Royal, at Edinburg Gap (S.R. 675) towards Edinburg, Moreland Gap (S.R. 730) towards New Market, and Edith Gap (S.R. 675) towards Luray. There is also a dirt road that leads to Woodstock (S.R 758) over Powell Mountain.