Area codes in Chino Hills, California
Chino Hills, California uses 2 area codes — 909 and 840. The main Chino Hills area code is 909.
Area codes serving Chino Hills
Phone numbers in Chino Hills are written as ten digits — for example (909) 555-0190 — and fall in the Pacific Time zone.
How Chino Hills came to have 2 area codes
The original Chino Hills area code is 909, in service since 1992. As the area ran low on available numbers, an overlay code was added over the same region for new phone lines: 840 (2021). Existing numbers kept their original code — an overlay never forces anyone to change their number — which is why Chino Hills 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 Chino Hills?
The main area code for Chino Hills, California is 909. Chino Hills is now served by 2 area codes in total: 909, 840.
How many area codes does Chino Hills have?
Chino Hills has 2 area codes: 909, 840.
Why does Chino Hills have more than one area code?
As Chino Hills used up the numbers available in its original area code (909, in service since 1992), additional "overlay" codes were added over the same area so new phone numbers could keep being assigned.
How do you dial a Chino Hills number?
Dial all 10 digits — the area code (909 or 840) 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.