| ZIP Codes: | 77 ZIP Codes (42 Standard, 25 PO Box, 10 Unique) [See All] |
| Area Codes: | 227 / 240 / 301 |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 2:12:29 PM |
| Population: | 1,076,754 [See All] |
| FIPS: | 24031 |
| CBSA: | Washington-Arlington-Alexandria, DC-VA-MD-WV |
| Land Area: | 519 sq mi |
| Water Area: | 14 sq mi |
| Coordinates: | 39.0828, -77.1274 |
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1,076,754 residents live across 77 ZIPs covering 519 sq mi, served by 30 distinct USPS-recognized cities.
Population moved from 1,014,156 to 1,076,170 from 2014 to 2024 — a +6.1% change. 33 ZIPs gained residents, 12 lost.
The county's wealthiest ZIP 20854 (Potomac, $250,001 median) and poorest ZIP 20903 (Silver Spring, $80,768) are 11.9 miles apart — a 3.1× income gap across local geography.
Median home values vary 3.5× across this county — from $386,500 in 20886 (Montgomery Village) to $1,335,100 in 20818 (Cabin John).
Density varies 241× across the county — from 41 people/sq mi in 20842 (Dickerson) to 9,944 in 20910 (Silver Spring).
Educational attainment ranges from 27.2% bachelor's+ in 20903 (Silver Spring) to 88.5% in 20816 (Bethesda) — the breadth of educational profiles across the area.
Within Maryland, this is the #1 most populous of 24 counties and ranks #2 for median household income with the #8 fastest decade growth .
On the national stage, Montgomery County is the #44 most populous US county , ranks #15 for income .
Hosts 4 single-entity Unique ZIPs: 20899Natl Inst Stds & Tech Md ; 20889Walter Reed Natl Mil Med Ctr ; 20993Us Food And Drug Admin ; and 20892National Institute Of Health .
Weighted by population, the typical household earns about $140,343 across the county — reflecting what a typical resident sees, not a simple ZIP average.
60.3% of adults age 25+ hold a bachelor's degree or higher (451,045 of 747,411 reporting).
42 Standard delivery, 25 PO Box only, 10 single-entity Unique ZIPs serve this county.
16 ZIPs in this county where more than 60% of adults 25+ hold a bachelor's degree — typically college campuses, research enclaves, or tech corridors.
10 ZIP codes in this county serve a single facility — typically theme parks, universities, large corporations, airports, or government complexes.
Median household income spans 3.1× between the wealthiest and poorest ZIPs — a sign of significant intra-county inequality.
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 20906 | Silver Spring | Standard | 70,595 | $97,521 | 12.2 | 2.7% |
| 20878 | Gaithersburg | Standard | 66,115 | $144,313 | 20.0 | 3.5% |
| 20874 | Germantown | Standard | 62,738 | $115,022 | 23.1 | 8.2% |
| 20904 | Silver Spring | Standard | 58,646 | $96,025 | 13.8 | 4.0% |
| 20902 | Silver Spring | Standard | 54,261 | $114,486 | 7.6 | 6.4% |
| 20854 | Potomac | Standard | 50,498 | $250,001 | 36.5 | 0.3% |
| 20850 | Rockville | Standard | 50,353 | $125,950 | 14.4 | 7.8% |
| 20852 | Rockville | Standard | 48,180 | $122,472 | 8.1 | 8.0% |
| 20910 | Silver Spring | Standard | 45,943 | $112,134 | 4.6 | 15.8% |
| 20877 | Gaithersburg | Standard | 38,546 | $92,800 | 5.7 | 4.7% |
| 20817 | Bethesda | Standard | 37,454 | $249,332 | 14.3 | 3.8% |
| 20901 | Silver Spring | Standard | 36,435 | $131,386 | 5.3 | 0.3% |
| 20886 | Montgomery Village | Standard | 34,718 | $98,542 | 4.3 | 1.1% |
| 20814 | Bethesda | Standard | 32,795 | $150,996 | 4.4 | 16.5% |
| 20853 | Rockville | Standard | 31,851 | $159,080 | 9.3 | 5.9% |
| 20815 | Chevy Chase | Standard | 30,505 | $194,971 | 5.4 | -0.1% |
| 20871 | Clarksburg | Standard | 30,182 | $177,523 | 23.0 | 98.0% |
| 20876 | Germantown | Standard | 26,406 | $119,731 | 10.8 | 0.4% |
| 20912 | Takoma Park | Standard | 25,749 | $83,870 | 2.7 | 3.0% |
| 20832 | Olney | Standard | 25,553 | $168,524 | 10.1 | -1.7% |
| 20879 | Gaithersburg | Standard | 25,264 | $112,104 | 8.2 | -1.3% |
| 20903 | Silver Spring | Standard | 24,815 | $80,768 | 3.0 | -2.8% |
| 20895 | Kensington | Standard | 19,184 | $173,625 | 4.0 | -0.5% |
| 20905 | Silver Spring | Standard | 19,004 | $159,740 | 12.3 | 6.4% |
| 20816 | Bethesda | Standard | 18,140 | $232,656 | 4.2 | 9.2% |
| 20855 | Derwood | Standard | 17,279 | $149,110 | 13.1 | 21.9% |
| 20866 | Burtonsville | Standard | 15,986 | $140,308 | 7.1 | 23.9% |
| 20851 | Rockville | Standard | 14,946 | $126,411 | 2.4 | 4.1% |
| 20872 | Damascus | Standard | 13,983 | $141,050 | 20.4 | 5.6% |
| 20882 | Gaithersburg | Standard | 13,751 | $184,136 | 38.5 | -4.5% |
| 20841 | Boyds | Standard | 9,969 | $184,688 | 29.7 | -5.5% |
| 20833 | Brookeville | Standard | 7,860 | $204,375 | 19.0 | 0.4% |
| 20837 | Poolesville | Standard | 6,699 | $174,063 | 43.3 | 12.9% |
| 20861 | Ashton | Standard | 2,890 | $163,438 | 5.3 | 44.6% |
| 20842 | Dickerson | Standard | 2,369 | $204,013 | 57.4 | 26.1% |
| 20860 | Sandy Spring | Standard | 2,035 | — | 3.4 | -13.3% |
| 20818 | Cabin John | Standard | 1,539 | $245,982 | 1.4 | -21.0% |
| 20896 | Garrett Park | PO Box | 932 | $250,001 | 0.3 | -7.3% |
| 20889 | Bethesda | Unique | 584 | — | 0.4 | — |
| 20880 | Washington Grove | PO Box | 577 | $134,583 | 0.3 | 7.2% |
| 20862 | Brinklow | Standard | 430 | $189,667 | 2.1 | 179.2% |
| 20838 | Barnesville | Standard | 306 | $250,001 | 1.6 | 53.0% |
| 20812 | Glen Echo | Standard | 276 | $213,750 | 0.1 | 8.2% |
| 20868 | Spencerville | Standard | 198 | $143,333 | 1.6 | -83.5% |
| 20839 | Bealsville | Standard | 158 | $160,329 | 2.5 | 42.3% |
| 20899 | Gaithersburg | Unique | 57 | $24,417 | 0.7 | -56.5% |
| 20892 | Bethesda | Unique | 0 | — | 0.3 | — |
| 20894 | Bethesda | Unique | 0 | — | 0.1 | — |
| 20907 | Silver Spring | PO Box | — | — | 0.0 | — |
| 20911 | Silver Spring | PO Box | — | — | 0.0 | — |
| 20825 | Chevy Chase | PO Box | — | — | 0.0 | — |
| 20913 | Takoma Park | PO Box | — | — | 0.0 | — |
| 20813 | Bethesda | PO Box | — | — | 0.0 | — |
| 20824 | Bethesda | PO Box | — | — | 0.0 | — |
| 20811 | Bethesda | Unique | — | — | 0.0 | — |
| 20810 | Bethesda | Unique | — | — | 0.0 | — |
| 20915 | Silver Spring | PO Box | — | — | 0.0 | — |
| 20891 | Kensington | PO Box | — | — | 0.0 | — |
| 20847 | Rockville | PO Box | — | — | 0.0 | — |
| 20857 | Rockville | Unique | — | — | 0.0 | — |
| 20914 | Silver Spring | PO Box | — | — | 0.0 | — |
| 20848 | Rockville | PO Box | — | — | 0.0 | — |
| 20827 | Bethesda | PO Box | — | — | 0.0 | — |
| 20993 | Silver Spring | Unique | — | — | 0.4 | — |
| 20859 | Potomac | PO Box | — | — | 0.0 | — |
| 20918 | Silver Spring | PO Box | — | — | 0.0 | — |
| 20885 | Gaithersburg | PO Box | — | — | 0.0 | — |
| 20884 | Gaithersburg | PO Box | — | — | 0.0 | — |
| 20883 | Gaithersburg | PO Box | — | — | 0.0 | — |
| 20898 | Gaithersburg | PO Box | — | — | 0.0 | — |
| 20916 | Silver Spring | PO Box | — | — | 0.0 | — |
| 20897 | Suburb Maryland Fac | Unique | — | — | 0.0 | — |
| 20849 | Rockville | PO Box | — | — | 0.0 | — |
| 20997 | Silver Spring | Unique | — | — | 0.0 | — |
| 20908 | Silver Spring | PO Box | — | — | 0.0 | — |
| 20875 | Germantown | PO Box | — | — | 0.0 | — |
| 20830 | Olney | PO Box | — | — | 0.0 | — |