| ZIP Codes: | 12 ZIP Codes (7 Standard, 5 PO Box, 0 Unique) [See All] |
| Area Codes: | 305 / 645 / 786 |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 2:11:39 PM |
| Population: | 81,805 [See All] |
| FIPS: | 12087 |
| CBSA: | Key West-Key Largo, FL |
| Land Area: | 138 sq mi |
| Water Area: | 497 sq mi |
| Coordinates: | 24.7677, -81.1483 |
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81,805 residents live across 12 ZIPs covering 138 sq mi, served by 10 distinct USPS-recognized cities.
Population moved from 75,167 to 81,805 from 2014 to 2024 — a +8.8% change. 6 ZIPs gained residents, 3 lost.
The county's wealthiest ZIP 33043 (Big Pine Key, $110,491 median) and poorest ZIP 33070 (Tavernier, $75,436) are 58.4 miles apart — a 1.5× income gap across local geography.
Median home values vary 1.6× across this county — from $638,000 in 33043 (Big Pine Key) to $1,017,400 in 33036 (Islamorada).
Density varies 7× across the county — from 254 people/sq mi in 33042 (Summerland Key) to 1,831 in 33040 (Key West).
Educational attainment ranges from 30.7% bachelor's+ in 33043 (Big Pine Key) to 46.7% in 33042 (Summerland Key) — the breadth of educational profiles across the area.
Within Florida, this is the #38 most populous of 67 counties and ranks #6 for median household income with the #35 fastest decade growth .
Weighted by population, the typical household earns about $89,446 across the county — reflecting what a typical resident sees, not a simple ZIP average.
38.6% of adults age 25+ hold a bachelor's degree or higher (24,945 of 64,568 reporting).
7 Standard delivery, 5 PO Box only, 0 single-entity Unique ZIPs serve this county.
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 33040 | Key West | Standard | 35,429 | $86,586 | 19.4 | 5.2% |
| 33037 | Key Largo | Standard | 14,770 | $86,533 | 54.6 | 22.8% |
| 33050 | Marathon | Standard | 10,561 | $94,898 | 9.3 | 15.4% |
| 33042 | Summerland Key | Standard | 6,441 | $103,041 | 25.4 | 1.8% |
| 33070 | Tavernier | Standard | 5,768 | $75,436 | 4.5 | 23.6% |
| 33043 | Big Pine Key | Standard | 4,298 | $110,491 | 16.2 | -6.4% |
| 33036 | Islamorada | Standard | 3,777 | $86,032 | 6.2 | -3.7% |
| 33051 | Key Colony Beach | PO Box | 511 | $94,231 | 0.5 | -16.9% |
| 33001 | Long Key | PO Box | 250 | — | 1.9 | 30.9% |
| 33052 | Marathon Shores | PO Box | — | — | 0.0 | — |
| 33041 | Key West | PO Box | — | — | 0.0 | — |
| 33045 | Key West | PO Box | — | — | 0.0 | — |