Numbers with prefix 840 in United States
Landline California
In United States's numbering plan, the area code 840 covers California. It identifies where a line was allocated, not who is calling: numbers are portable and caller ID can be spoofed, so the digits alone do not identify the caller.
Search a number with prefix 840
Search a phone number or a company name (Bank of America, Verizon and AT&T...) to check if it has been reported as spam.
Numbers reported with prefix 840
8 numbersAbout numbers 840
Numbers starting with 840 may include toll-free (800) or premium-rate (803, 806, 807) services. Be careful with premium-rate numbers — calling back can be expensive.
Official source and review
Google libphonenumber (compiled from national numbering plans) · Document: 2026-08-28 · Reviewed: 2026-08-31
A prefix describes an official allocation. Portability and caller-ID spoofing mean it cannot identify the caller on its own.