A guide to 3-digit N11 phone numbers is located here.

• 211 - Community information and referral services. 211 service is provided by local community-based or government organizations that are authorized by the CPUC to use the 211 code to provide information and referrals to health and human services.
• 311 - Non-emergency governmental services. 311 service is administered by municipal governments.
• 411 - Local Directory Assistance. 411 directory assistance is provided by individual telecommunications service providers or independent providers.
• 511 - Traffic and Transportation information. The California Highway Patrol, California Department of Transportation, and local transportation agencies oversee 511 operations.
• 611 - General Customer Service. 611 service is provided by individual telecommunications service providers.
• 711 - Telecommunications Relay Service for the speech and hearing impaired. In California, 711 Relay service is provided through Hamilton Relay.
• 811 - Call-before-you-dig phone number for access to location of buried utilities. Underground Service Alert, a nonprofit organization, manages 811 calls and operates two call centers: USA North 811 for northern California and Dig Alert for southern California.
• 911 - Emergency services. The California Office of Emergency Services and local public safety agencies oversee 911 emergency service operations.
• 988 - National Suicide Prevention Lifeline. The United States Department of Health and Human Services' Substance Abuse and Mental Health Services Administration, in partnership with the Department of Veterans Affairs, administers the National Suicide Prevention Lifeline, which is a national network of approximately 170 local and state funded crisis centers.
  
  

Web pages

• California Area Codes & Numbering - https://www.cpuc.ca.gov/areacodes/