Monroe County Flood Zones
County seat: Key West. 81,840 residents. Florida Keys.
Flood risk in Monroe County
Situated within the Keys region, Monroe County faces extreme storm surge risk and high rain flood risk due to its entirely coastal geography and low elevation. This archipelago county, home to over 81,000 residents, is uniquely exposed to Atlantic and Gulf of Mexico systems, with major municipalities like Key West and Marathon frequently bearing the brunt of severe weather events. Recent federal disaster declarations highlight the intensity of this exposure, including the impacts of Hurricane Milton in 2024 and Hurricane Irma in 2017, which caused widespread damage across the island chain. The combination of high water tables, limited drainage options, and the constant threat of tropical cyclones means that flooding can occur rapidly during heavy rainfall or high tides, regardless of a property's distance from the immediate shoreline. Residents in communities such as Islamorada and Key Colony Beach must remain vigilant about both wind-driven surge and inland water accumulation. Given the frequency of these events, verifying your specific flood zone and understanding your evacuation route before the start of each storm season is essential for safety and financial preparedness.
Risk profile
Situated within the keys region, this coastal county contends with extreme storm surge risk and high rain flood risk across its populated areas. With a population exceeding 81,000, major municipalities including Key West and Marathon have experienced multiple federal disaster declarations, such as Hurricane Milton in 2024 and Hurricane Irma in 2017.
Recent FEMA-declared storms
Tropical systems that triggered federal disaster declarations covering Monroe County (most recent first):
- Hurricane Milton (2024)
- TS Helene (2024)
- TS Debby (2024)
- Hurricane Ian (2022)
- Hurricane Isaias (2020)
- Hurricane Dorian (2019)
- Hurricane Irma (2017)
- Hurricane Matthew (2016)
Source: OpenFEMA Disaster Declarations Summaries.
Major cities in Monroe County
- Key West25,240
- Marathon10,039
- Islamorada, Village of Islands7,013
- Key Colony Beach749
- Layton208
Source: US Census SUB-EST 2024.
Need real numbers, not estimates?
Buying or selling in Monroe County? A local Florida agent can tell you how flood zone affects price, insurance, and closing.
FAQ
What flood zones are in Monroe County?
Monroe County contains a mix of FEMA flood zones. Coastal and low-lying areas typically fall in Special Flood Hazard Areas (zones AE, A, VE), while higher-elevation areas are usually Zone X. Use the lookup tool above to check any specific address against the live National Flood Hazard Layer.
What hurricanes have impacted Monroe County recently?
Storms that triggered FEMA disaster declarations covering Monroe County since 2020: Milton (2024), Helene (2024), Debby (2024), Ian (2022), Isaias (2020). Federal disaster declarations cover both direct landfall counties and surrounding counties eligible for federal assistance.
Is flood insurance required in Monroe County?
Flood insurance is federally required for any property in a Special Flood Hazard Area (zones beginning with A or V) that has a federally backed mortgage. In Zone X it is optional but often inexpensive. The lookup tool above tells you whether a specific address falls in an SFHA.
How does storm surge affect Monroe County?
As a Florida Keys county, Monroe faces extreme storm surge risk during tropical systems. Storm surge is separate from rainfall flooding and is not always reflected in FEMA flood zone designations — check your county's evacuation zone as well.
What is the population of Monroe County?
81,840 residents (ACS5 2023, US Census). The county seat is Key West.
Sources: FEMA National Flood Hazard Layer, OpenFEMA Disaster Declarations, US Census Bureau (ACS 5-year, SUB-EST 2024), Florida Department of Environmental Protection. Flood zone designations and risk profiles change over time — always verify with the official lookup before making property decisions.