Multistate Tax Commission
- Organization of state governments that works with taxpayers to administer tax laws that apply to multistate enterprises.
- http://www.mtc.gov/

Federation of Tax Administrators
- Organization of state tax officials. Includes comparative information on state tax agencies, rates, policies, and administration, as well as links to individual agencies.
- http://www.taxadmin.org/

Center for Policy Alternatives
- Organization working to strengthen the capacity of state legislators to lead and achieve progressive change. Features issues analyses, announcements of programs and events, and directories of related resources.
- http://www.cfpa.org

Council of State Governments
- Current news (updated daily), research, internet links, and other information of value to people involved or interested in state government.
- http://www.csg.org/CSG/

Environmental Council of the States (ECOS)
- National non-profit, non-partisan association of state and territorial environmental commissioners.
- http://www.ecos.org/

State Services Organization (SSO)
- Offering services to Washington-based state government organizations at the Hall of the States office building.
- http://www.sso.org/

The State International Development Organizations (SIDO)
- Dedicated to supporting state international trade agencies. SIDO helps state governments assist American exporters through a wide range of professional development, advocacy, and trade promotion programs.
- http://www.sidoamerica.org/

National Association of State Chief Information Officers
- Represents state chief information officers and information resource executives and managers from U.S. states, territories, and the District of Columbia. Information on the organization, professional resources, and current issues, particularly in the area
- https://www.nascio.org/

National Association of State Budget Officers
- Professional membership organization for state financial officers, serving as the instrument by which the states collectively advance state budget practices.
- http://www.nasbo.org/

National Governors Association
- News and information from the National Governors Association (NGA) and the NGA Center for Best Practices. Site includes information on the U.S. governors and dozens of U.S. domestic policy issues.
- http://www.nga.org