| ZIP Codes: | 34 ZIP Codes (17 Standard, 11 PO Box, 6 Unique) [See All] |
| Area Codes: | 540 / 571 / 703 / 826 |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 11:55:30 PM |
| Population: | 430,542 [See All] |
| FIPS: | 51107 |
| CBSA: | Washington-Arlington-Alexandria, DC-VA-MD-WV |
| Land Area: | 488 sq mi |
| Water Area: | 5 sq mi |
| Coordinates: | 39.0639, -77.5681 |
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430,542 residents live across 34 ZIPs covering 488 sq mi, served by 16 distinct USPS-recognized cities.
Population moved from 336,635 to 430,542 from 2014 to 2024 — a +27.9% change. 15 ZIPs gained residents, 1 lost.
The county's wealthiest ZIP 20148 (Ashburn, $233,494 median) and poorest ZIP 20166 (Sterling, $133,401) are 3.9 miles apart — a 1.8× income gap across local geography.
Median home values vary 2.0× across this county — from $544,300 in 20164 (Sterling) to $1,080,200 in 20197 (Waterford).
Density varies 100× across the county — from 56 people/sq mi in 20117 (Middleburg) to 5,618 in 20164 (Sterling).
Educational attainment ranges from 37.6% bachelor's+ in 20164 (Sterling) to 77.7% in 20148 (Ashburn) — the breadth of educational profiles across the area.
Within Virginia, this is the #4 most populous of 134 counties and ranks #1 for median household income with the #2 fastest decade growth .
On the national stage, Loudoun County is ranks #2 for income , and #72 for decade growth .
Hosts 4 single-entity Unique ZIPs: 20598Falls Church ; 20103Stamp Distribution Network ; 20149Natl Assn Letter Carriers ; and 20104Inspection Service Forensic .
Weighted by population, the typical household earns about $183,102 across the county — reflecting what a typical resident sees, not a simple ZIP average.
64.6% of adults age 25+ hold a bachelor's degree or higher (182,296 of 282,269 reporting).
17 Standard delivery, 11 PO Box only, 6 single-entity Unique ZIPs serve this county.
10 ZIPs in this county where more than 60% of adults 25+ hold a bachelor's degree — typically college campuses, research enclaves, or tech corridors.
6 ZIP codes in this county serve a single facility — typically theme parks, universities, large corporations, airports, or government complexes.
Loudoun County grew 27.9% over the past decade — concentrated in 5 high-growth ZIPs:
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 20147 | Ashburn | Standard | 67,692 | $163,904 | 20.1 | 14.0% |
| 20148 | Ashburn | Standard | 64,021 | $233,494 | 18.6 | 84.1% |
| 20176 | Leesburg | Standard | 51,471 | $168,299 | 55.4 | 5.3% |
| 20164 | Sterling | Standard | 43,436 | $135,660 | 7.7 | 11.2% |
| 20105 | Aldie | Standard | 37,639 | $219,123 | 37.4 | 175.8% |
| 20152 | Chantilly | Standard | 36,674 | $197,156 | 13.3 | 31.8% |
| 20175 | Leesburg | Standard | 34,733 | $174,854 | 59.4 | 13.5% |
| 20165 | Sterling | Standard | 34,088 | $183,076 | 9.9 | 2.5% |
| 20132 | Purcellville | Standard | 19,817 | $181,875 | 83.2 | 13.0% |
| 20166 | Sterling | Standard | 14,949 | $133,401 | 29.4 | 50.3% |
| 20141 | Round Hill | Standard | 8,359 | $210,563 | 26.6 | 33.2% |
| 20180 | Lovettsville | Standard | 7,531 | $151,483 | 43.7 | 17.2% |
| 20158 | Hamilton | Standard | 4,979 | $211,522 | 12.4 | 18.7% |
| 20117 | Middleburg | Standard | 2,790 | $146,120 | 49.6 | 13.9% |
| 20197 | Waterford | Standard | 1,825 | $190,703 | 15.0 | 9.5% |
| 20129 | Paeonian Springs | Standard | 538 | $250,001 | 6.4 | -26.7% |
| 20178 | Leesburg | PO Box | — | — | 0.0 | — |
| 20160 | Lincoln | PO Box | — | — | 0.0 | — |
| 20134 | Purcellville | PO Box | — | — | 0.0 | — |
| 20159 | Hamilton | PO Box | — | — | 0.0 | — |
| 20598 | Dhs | Unique | — | — | 0.0 | — |
| 20103 | Dulles | Unique | — | — | 0.0 | — |
| 20189 | Dulles | Standard | — | — | 0.0 | — |
| 20149 | Ashburn | Unique | — | — | 0.0 | — |
| 20131 | Philomont | PO Box | — | — | 0.0 | — |
| 20142 | Round Hill | PO Box | — | — | 0.0 | — |
| 20177 | Leesburg | PO Box | — | — | 0.0 | — |
| 20104 | Dulles | Unique | — | — | 0.0 | — |
| 20102 | Dulles | Unique | — | — | 0.0 | — |
| 20118 | Middleburg | PO Box | — | — | 0.0 | — |
| 20167 | Sterling | PO Box | — | — | 0.0 | — |
| 20146 | Ashburn | PO Box | — | — | 0.0 | — |
| 20101 | Dulles | Unique | — | — | 0.0 | — |
| 20163 | Sterling | PO Box | — | — | 0.0 | — |