Area Code Lookup
What Area Code Is Eureka?
2 area codes serve Eureka
Eureka is served by area codes 636, 707. It spans Missouri and California.
Area Codes Serving Eureka
Frequently Asked Questions
What area code is Eureka?
Eureka is served by area codes 636, 707.
Why does Eureka have multiple area codes?
As demand for phone numbers increased, NANPA added area codes through splits (dividing the region) or overlays (layering a new code over the same geography). Eureka now has 2 area codes — 636 and 707 — covering the same or overlapping areas.
How do I call Eureka from outside the US?
To call Eureka from abroad, dial +1 followed by the area code and 7-digit local number (e.g. +1-636-XXX-XXXX). The +1 is the country code for all NANPA countries.