3-1-1 compared to 2-1-1

3-1-1 and 2-1-1 are special local numbers that take a ‘local caller’ to a call center for that community. Note that the call center you reach depends on the area code you are dialing from. In general 3-1-1 numbers take you to a call center for local city and government services while the 2-1-1 number take you to a local call center for health and human services organizations.

Both 3-1-1 and 2-1-1 came about from local governments wanting to keep non-emergency calls going to the 9-1-1 call centers. As a reminder the 9-1-1 local call service is the emergency phone number for emergencies in the United States, the Caribbean and U.S. Territories.

Here are examples of local 3-1-1 and 2-1-1 Call Centers in Colorado

Denver 311
Using Denver, Colorado as an example if you call 3-1-1 and you are calling from a Denver area code you will be connected with someone who could refer you to items such as vehicle registration, property information, propery tax instructions, police department non-emergency, clerk and recorder records requests, marriage license inquiry and other topics.
Website: https://www.denvergov.org/Government/Agencies-Departments-Offices/Agencies-Departments-Offices-Directory/311-City-Services

211 Colorado
2-1-1 Colorado connects families and individuals to health and human services organizations best suited to meet their need in the state of Colorado. 211 Colorado covers the entire state and the system is organized by local United Way Chapters. The 211 Colorado system has an extensive website for searching local services.
Website: https://www.211colorado.org/

To find 2-1-1 for your State

The Federal Communications Commission (FCC) designated 211 as the 3-digit number for information and referrals to social services and other assistance in 2000. The 211 service is provided by more than 200 local organizations that are committed to serving their communities. Many different kinds of organizations operate the 211 service, including United Ways, Goodwill, Community Action Partnerships, and local crisis centers.
Website: https://www.211.org/

Where did the Concept of 311, 211 and 911 come from?

The idea of incorporating a standardized phone numbering system started with the North American Numbering Plan (NANP) originally developed by the Bell System in the 1940s. The Bell System numbering plan proposed that phone numbers should be coordinated across geographic locations. The history of the plan from its early days to the implementation of our current system is a fascinating story how telephone technology impacted the United States and neighboring countries. To learn more about the North American Numbering Plan visit the website Wikipedia and look up North American Numbering Plan.
Website: https://en.wikipedia.org/