Area Code Lookup
What Area Code Is Mill Valley?
Area code 415 · California
Mill Valley uses area code 415. It is located in California.
Area Code Serving Mill Valley
Frequently Asked Questions
What area code is Mill Valley?
Mill Valley uses area code 415. It is located in California.
How do I call Mill Valley from outside the US?
To call Mill Valley from abroad, dial +1 followed by the area code and 7-digit local number (e.g. +1-415-XXX-XXXX). The +1 is the country code for all NANPA countries.