Area codes in Hillsboro, Oregon
Hillsboro, Oregon uses 2 area codes — 503 and 971. The main Hillsboro area code is 503.
Area codes serving Hillsboro
Phone numbers in Hillsboro are written as ten digits — for example (503) 555-0190 — and fall in the Pacific Time zone.
How Hillsboro came to have 2 area codes
The original Hillsboro area code is 503, in service since 1947. As the area ran low on available numbers, an overlay code was added over the same region for new phone lines: 971 (2000). Existing numbers kept their original code — an overlay never forces anyone to change their number — which is why Hillsboro now uses all 2 codes and every local call is dialed with ten digits.
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Frequently asked questions
What is the area code for Hillsboro?
The main area code for Hillsboro, Oregon is 503. Hillsboro is now served by 2 area codes in total: 503, 971.
How many area codes does Hillsboro have?
Hillsboro has 2 area codes: 503, 971.
Why does Hillsboro have more than one area code?
As Hillsboro used up the numbers available in its original area code (503, in service since 1947), additional "overlay" codes were added over the same area so new phone numbers could keep being assigned.
How do you dial a Hillsboro number?
Dial all 10 digits — the area code (503 or 971) followed by the 7-digit local number. From abroad, dial +1, then the area code and number.
Sourced from the official NANPA (North American Numbering Plan Administrator) numbering database, current as of August 2, 2026. Refreshed monthly.