| ZIP Codes: | 27 ZIP Codes (24 Standard, 3 PO Box, 0 Unique) [See All] |
| Area Codes: | 227 / 240 / 301 |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 11:13:41 PM |
| Population: | 113,480 [See All] |
| FIPS: | 24037 |
| CBSA: | Lexington Park, MD |
| Land Area: | 419 sq mi |
| Water Area: | 85 sq mi |
| Coordinates: | 38.2438, -76.5673 |
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113,480 residents live across 27 ZIPs covering 419 sq mi, served by 27 distinct USPS-recognized cities.
Population moved from 106,848 to 113,393 from 2014 to 2024 — a +6.1% change. 13 ZIPs gained residents, 12 lost.
The county's wealthiest ZIP 20684 (Saint Inigoes, $180,060 median) and poorest ZIP 20670 (Patuxent River, $70,371) are 10.0 miles apart — a 2.6× income gap across local geography.
Median home values vary 1.7× across this county — from $342,300 in 20634 (Great Mills) to $592,400 in 20674 (Piney Point).
Density varies 74× across the county — from 43 people/sq mi in 20609 (Avenue) to 3,211 in 20686 (Saint Marys City).
Educational attainment ranges from 15.8% bachelor's+ in 20621 (Chaptico) to 50.2% in 20619 (California) — the breadth of educational profiles across the area.
Within Maryland, this is the #12 most populous of 24 counties and ranks #4 for median household income with the #7 fastest decade growth .
On the national stage, Saint Marys County is ranks #37 for income .
Weighted by population, the typical household earns about $125,867 across the county — reflecting what a typical resident sees, not a simple ZIP average.
36.7% of adults age 25+ hold a bachelor's degree or higher (27,967 of 76,260 reporting).
24 Standard delivery, 3 PO Box only, 0 single-entity Unique ZIPs serve this county.
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 20653 | Lexington Park | Standard | 26,852 | $103,048 | 35.3 | 5.0% |
| 20659 | Mechanicsville | Standard | 24,324 | $121,654 | 101.3 | 1.3% |
| 20650 | Leonardtown | Standard | 16,094 | $143,116 | 68.0 | 19.5% |
| 20619 | California | Standard | 14,212 | $119,432 | 17.5 | 30.6% |
| 20636 | Hollywood | Standard | 10,486 | $163,690 | 44.7 | 2.0% |
| 20634 | Great Mills | Standard | 7,088 | $139,375 | 7.0 | 4.7% |
| 20670 | Patuxent River | Standard | 2,046 | $70,371 | 12.0 | 44.0% |
| 20618 | Bushwood | Standard | 1,705 | $105,508 | 11.4 | 110.2% |
| 20620 | Callaway | Standard | 1,115 | $165,972 | 4.3 | -13.6% |
| 20690 | Tall Timbers | Standard | 1,077 | $122,750 | 2.3 | 89.9% |
| 20686 | Saint Marys City | PO Box | 971 | — | 0.3 | -4.8% |
| 20621 | Chaptico | Standard | 958 | — | 19.6 | -30.8% |
| 20684 | Saint Inigoes | Standard | 802 | $180,060 | 12.3 | -28.1% |
| 20624 | Clements | Standard | 796 | $104,545 | 10.4 | -35.2% |
| 20674 | Piney Point | Standard | 769 | $171,985 | 3.6 | -5.4% |
| 20609 | Avenue | Standard | 714 | $118,102 | 16.5 | -34.5% |
| 20680 | Ridge | Standard | 663 | — | 9.2 | -54.6% |
| 20630 | Drayden | Standard | 559 | $233,411 | 15.4 | 92.1% |
| 20692 | Valley Lee | Standard | 505 | $201,250 | 7.4 | -69.9% |
| 20628 | Dameron | Standard | 503 | — | 7.8 | 278.2% |
| 20687 | Scotland | Standard | 415 | — | 6.0 | 9.5% |
| 20606 | Abell | Standard | 291 | $88,262 | 1.3 | -28.7% |
| 20626 | Coltons Point | Standard | 284 | — | 1.6 | 15.0% |
| 20667 | Park Hall | Standard | 150 | — | 2.8 | -69.1% |
| 20656 | Loveville | Standard | 87 | — | 0.6 | — |
| 20660 | Morganza | PO Box | 14 | — | 0.2 | -50.0% |
| 20627 | Compton | PO Box | — | — | 0.0 | — |