Founded in 1757, Loudoun County is one of 95 counties in the state of Virginia. Historically, Loudoun County was formed from Fairfax County. The city of Leesburg is the county seat. With FIPS code of 107, Loudoun County has a population of 427,592 and area of 520 square miles (1,347 km2).
List of all cities in Loudoun County, VA alphabetically
| City/Town | Postal Code | Area Code |
| Aldie, VA | 20105 | 703/571 |
| Alexandria, VA | 20598 | 202 |
| Arcola, VA | 20148 | 703/571 |
| Arlington, VA | 20598 | 202 |
| Ashburn, VA | 20146 | 703/571 |
| 20147 | 703/571 | |
| 20148 | 703/571 | |
| 20149 | 703/571 | |
| Brambleton, VA | 20148 | 703/571 |
| Broadlands, VA | 20148 | 703/571 |
| Chantilly, VA | 20152 | 703/571 |
| Dept HS, VA | 20598 | 202 |
| DHS, VA | 20598 | 202 |
| Dulles, VA | 20101 | 703/571 |
| 20102 | 703/571 | |
| 20103 | 703/571 | |
| 20104 | 703/571 | |
| 20163 | 703/571 | |
| 20166 | 703/571 | |
| 20189 | 540 | |
| Dulles Air Mail Facility, VA | 20102 | 703/571 |
| Dulles Air Transfer Office, VA | 20102 | 703/571 |
| Dulles P & D Center, VA | 20101 | 703/571 |
| Fairfax, VA | 20152 | 703/571 |
| 20598 | 202 | |
| Falls Church, VA | 20598 | 202 |
| Hamilton, VA | 20158 | 540 |
| 20159 | 540 | |
| Herndon, VA | 20598 | 202 |
| Hillsboro, VA | 20132 | 540 |
| 20134 | 540 | |
| Inspection Service Forensic, VA | 20104 | 703/571 |
| Lansdowne, VA | 20176 | 703/571 |
| Leesburg, VA | 20175 | 703/571 |
| 20176 | 703/571 | |
| 20177 | 703/571 | |
| 20178 | 703/571 | |
| Lincoln, VA | 20160 | 540 |
| Lorton, VA | 20598 | 202 |
| Lovettsville, VA | 20180 | 540 |
| Lucketts, VA | 20176 | 703/571 |
| McLean, VA | 20598 | 202 |
| Middleburg, VA | 20117 | 540 |
| 20118 | 540 | |
| National Assn Letter Carriers, VA | 20149 | 703/571 |
| Paeonian Springs, VA | 20129 | 540 |
| Philomont, VA | 20131 | 540 |
| Potomac Falls, VA | 20165 | 703/571 |
| Purcellville, VA | 20132 | 540 |
| 20134 | 540 | |
| 20160 | 540 | |
| Reston, VA | 20598 | 202 |
| Round Hill, VA | 20141 | 540 |
| 20142 | 540 | |
| South Riding, VA | 20152 | 703/571 |
| Springfield, VA | 20598 | 202 |
| Stamp Distribution Network, VA | 20103 | 703/571 |
| Sterling, VA | 20163 | 703/571 |
| 20164 | 703/571 | |
| 20165 | 703/571 | |
| 20166 | 703/571 | |
| 20167 | 703/571 | |
| 20598 | 202 | |
| Stone Ridge, VA | 20105 | 703/571 |
| Waterford, VA | 20197 | 540 |