Loudoun County, VA Building Setbacks & Zoning: Lot Coverage Limits (2026)

A defines how it is calculated: lot coverage is the total of all eligible structure footprints divided by the lot area, expressed as a percentage. Under the Base Density Division Option, the standard 1-lot-per-20-acre path for AR-1 land, overall lot coverage may reach 25 percent, but only 10 percent of the lot may carry residential or nonresidential building footprint; the remaining allowance is reserved for agricultural structures not open to the public, reflecting the district's purpose of sustaining working farms and the rural economy. The Principal/Subordinate Subdivision Option (1 lot per 10 acres) and both branches of the Cluster Subdivision Option (Residential Cluster Lots and Rural Economy Cluster/Preservation Farm Lots, at 1 lot per 5 acres) instead cap total lot coverage at a flat 15 percent, with no separate agricultural carve-out.

Because AR-1 sits in the Rural Policy Area outside Leesburg, Purcellville, Hamilton, Middleburg, Round Hill, Hillsboro, and Lovettsville, these percentages apply only to unincorporated land; each town enforces its own coverage limits under its own zoning code. A property owner calculating coverage for a new barn, dwelling, or accessory building must total every structure footprint on the lot, divide by the recorded lot area, and confirm the result against whichever development option the parcel was subdivided under, since the applicable percentage swings by 10 points between options.