FEMA Flood Zones in Arapahoe County, Colorado

FEMA has mapped 29,050 acres of Arapahoe County, Colorado inside a Special Flood Hazard Area — the 1% annual chance floodplain, often called the 100-year floodplain. The map below shows every mapped flood zone inside the county boundary.

Arapahoe County, Colorado at a glance

Land in a FEMA Special Flood Hazard Area29,050 acres
Share of mapped land in a Special Flood Hazard Area5.7%
Share of the county with a published FEMA flood map100%
Largest mapped flood hazard area100-year flood (1% annual chance) — 23,886 acres
Distinct flood hazard categories mapped3
Distinct FEMA flood zone codes mapped5
Most widespread FEMA flood zoneZone X — 482,911 acres
Land in the 0.2% annual chance (500-year) floodplain2,534 acres
Land in a regulatory floodway5,163 acres

Arapahoe County, Colorado is home to 673,820 residents. Land Owl's FEMA flood zone layer records the following within the county boundary — Land in a FEMA Special Flood Hazard Area: 29,050 acres. Share of mapped land in a Special Flood Hazard Area: 5.7%. Share of the county with a published FEMA flood map: 100%. Largest mapped flood hazard area: 100-year flood (1% annual chance) — 23,886 acres. Distinct flood hazard categories mapped: 3. Distinct FEMA flood zone codes mapped: 5. Most widespread FEMA flood zone: Zone X — 482,911 acres. Land in the 0.2% annual chance (500-year) floodplain: 2,534 acres. Land in a regulatory floodway: 5,163 acres. Every feature shown on the map above is clickable, and the figures on this page are derived from the same data the map renders, so they always agree. A free Land Owl account adds parcel boundaries, ownership records, soils, wetlands and topography over the same view.

Frequently asked questions

How much of Arapahoe County, Colorado is in a FEMA flood zone?
Land Owl maps 29,050 acres of Arapahoe County, Colorado inside a Special Flood Hazard Area, which is 5.7% of the land FEMA has flood-mapped in the county. That is a regulatory designation used for floodplain management and federal flood-insurance requirements — it is not a prediction that the land will flood.
Is this flood zone map free to use?
Yes. This map is free to view. A free Land Owl account unlocks the other data layers, parcel boundaries and ownership records.
Where does this data come from?
Land Owl maps flood zones from FEMA's National Flood Hazard Layer (NFHL), the digital record of the effective Flood Insurance Rate Maps. It is a screening view, not a flood determination: FEMA revises maps, 495 US counties have never had a digital FIRM published at all, and a lender or insurer will ask for the official record. Check the FEMA Map Service Center, or ask your local floodplain administrator, before you rely on a zone.
Is land outside the flood zone safe from flooding?
No. A Special Flood Hazard Area marks where FEMA has studied and mapped a 1% annual chance of flooding; ground outside one has a lower mapped risk, not no risk, and some of it has never been studied at all. Roughly a quarter of US flood-insurance claims come from outside high-risk zones.
What is the difference between a 100-year and a 500-year flood zone?
They are shorthand for annual probability, not for how often a flood happens. A 100-year flood zone has a 1% chance of flooding in any given year; a 500-year zone has a 0.2% chance. Either can flood twice in a decade — the odds reset every year.

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