Cities in area code 650

15 localities · NANPA data, current as of July 28, 2026.

These are the cities and communities covered by 650 in California. "Covered" means the locality is a rate center holding 650 prefixes; the largest are Palo Alto, San Mateo, Mountain View.

By numbering footprint the leading localities are Palo Alto, San Mateo, Mountain View, South San Francisco, Redwood City, San Carlos-belmont, Los Altos and Millbrae, and 6 smaller communities down to single-prefix localities. Prefix counts track lines in service, so the ranking is a reasonable proxy for where the code's subscribers actually are.

15 of the localities fall within FCC top-100 metropolitan statistical areas; the rest are smaller communities.

1 of these localities are also reachable through other area codes — overlay territory where the same place answers to several codes.

All of the code's territory keeps Pacific time.

Remember that people keep numbers when they relocate, so a 650 number is a where-it-was-issued fact, not a where-they-are fact.

FAQ

What is the biggest city in area code 650?

Palo Alto holds the most active prefixes (144), making it the code's largest numbering locality.

How many places does 650 cover?

15 rate centers in California hold active 650 prefixes, from Palo Alto down to communities with a single prefix.

Does a 650 number guarantee the caller lives in one of these places?

No — the tables show where number blocks were issued. Porting and VoIP let people keep or acquire numbers anywhere.