NPA-NXX - 858-603

This is the 858-603 subcode (NPA-NXX) prefix page. Follow a prefix to find the number you are looking for. We divide our pages up to make them more user friendly to navigate!

1. Area Codes
2. 858
3. 858-603

The 858-603 subcode mainly covers Rancho Penasquitos in San Diego county. But other numbers maybe included as well.

We have a database of information derived from the public phone records of California state. Many of the numbers in this subcode are Cellular (Dedicated) registered to At&t Mobility. We hear they employ a large number of people in the California office.
Recently there have been an increase in reported calls, we've had over 3095313 comments across our systems for the 858-603 subcode.