Content management systems have proliferated in recent years, and there are now many viable open source content management systems. The current big name CMSs include Joomla!, Drupal, and WordPress. Wikipedia has a large list of content management systems, and a open source CMSs. The following is a list of government websites, particularly local governments, that are operated with an open source content management system. These are sites that I have come by, I know there are many others. If you see any, please leave a comment or contact me.

Local Governments

• Albert Lea, MN (see my article here) – WordPress
• Olathe, KS – Drupal
• Bloomington, IN – Civic-CMS (created the Civic-CMS and Bloomington has an open source statement)
• Portsmouth, VA Police Department – WordPress
• Snellville Downtown Development Authority – WordPress (this is a site I developed)
• Lawrence, KS – Drupal
• Macon, GA – Drupal (explanation)
• Dalton, GA – Joomla!
• Gwinnett Place Community Improvement District (Georgia) – Joomla!
• Gwinnett Village Community Improvement District (Georgia) – Joomla!
• RecoverySF, San Francisco’s Recovery Related site – WordPress (coverage)

States

• New York State Senate – Drupal (information here and here)

White House

• WhiteHouse.gov, The Executive Office of the President – Drupal (coverage here and here)

Federal

• Senator Jim DeMint (R-SC) – WordPress
• House Committee on Oversight and Government Reform (Republicans) – Joomla!
• Recovery.gov – was Drupal (mentioned here and here)
• IT Dashboard at USA Spending – Drupal (mentioned here)
• Business.gov (the Federal government’s business gateway) – Alfresco (mentioned here)
• Task Force Mountain, site of the 10th Mountain Division – Joomla!
• Department of Homeland Security’s National Terror Alert Response Center – WordPress
• CoLab at the National Aeronautics and Space Administration – Drupal
• Office of the Inspector General of the United States Postal Service – WordPress
• Congressional Budget Office Director’s Blog – WordPress (here)
• The United States Commission on International Religious Freedom – Joomla!
• Here is a list of Federal agencies that use WordPress (their sites are likely internal, so they aren’t using these for external portal sites)
• America.gov Blogs – WordPress
• The National Center for Preservation Technology & Training of the National Parks Service – WordPress (coverage here)
• Investor.gov from the Securities and Exchange Commission – WordPress (coverage here and here)
• Marines Magazine – WordPress (coverage here)
• Congresswoman Mary Bono Mack – WordPress (coverage here)
• NOAA Mission Log – WordPress (coverage here)

International

• Office of the Prime Minister of the United Kingdom – WordPress (my post here)
• Prime Minister of Australia – Drupal
• Prime Minister of Belgium – Drupal
• World Food Programme – Drupal (here)
• UK Power of Information Taskforce Report – WordPress (info here)
• UK DirectGov | Innovate – WordPress (info here)
• Portuguese Office of the High Commissioner for Health – WordPress
• Culture Ministry of Brazil – WordPress
• Print and Minting House of Chile – WordPress
• Cultura Digital, of the Brazil Culture Ministry – WordPress (specifically the social networking port, BuddyPress) with coverage here
• The King of Belgium – Drupal (info here)
• Queen Rania of Jordan – Drupal (info here)

Others

• Government Finance Officers Association – Joomla!
• Stanford University has quite a few sites running on Drupal
• Wake Forest University – WordPress (first post here)
• Duke University – Drupal
• Rutgers University – Drupal
• Amherst College – Drupal
• University of Prince Edward Island – Drupal
• University of Calgary – Drupal
• Davis Applied Technology College – Drupal (case study here)
• Big Ideas @ Berkeley – Drupal (case study here)
• NYU Child Study Center – Drupal (case study here)
• Student Activities (and many student organizations) at Texas A&M University – Drupal (case study here)
• Department of Arts and Sciences at Washington University – Drupal (info here)
• Virtual Pre-K by Chicago Public Schools – Drupal (info here)
• Strayer University – Drupal
• Portland State University – Drupal

Note: I add to this list as I come across sites using open source systems.  Please contact me if you know of others.

Note 2: WordPress has a showcase site (and specifically government sites here). Also, Drupal has a list of case studies of organizations that use Drupal (and a list of local governments using Drupal here and state and Federal usage list here).