Following the 1722 Treaty of Albany, which expelled Indigenous nations west of the Blue Ridge Mountains, white settlers began to occupy the Loudoun Valley.

The Quakers had significant influence in the central Loudoun Valley, settling in and around such communities as Waterford, Hillsboro, Goose Creek (now Lincoln), and Union (now Unison).

Germans settled in the northern end of the Loudoun Valley, especially in the area around Lovettsville, leaving a number of log structures as their architectural legacy.

In the southern portion of the valley, centered on Middleburg, settlers of English descent moving west from the Tidewater region imported slave-based plantation-style agriculture.

Stuart successfully kept the Federal forces from entering the adjacent Shenandoah Valley and discovering Robert E. Lee's main army.

In 1864, as General Jubal Early withdrew from Washington, Union forces attacked his supply wagons at Heaton's Crossroads at present-day Purcellville.

Following the war, the Loudoun Valley was slow to recover from the devastation of the Burning Raid, but soon the region became a major source of agricultural products again, particularly notable for its numerous dairy farms.

Corn, wheat, and beans remain staple crops, while berry production has increased dramatically (ranked first in the state).