National Conference of State Legislatures http://www.ncsl.org/
National Association of Counties http://www.naco.org/
Local Government Institute http://www.govtjob.net/local_govt__institute.htm
International City/County Management Association https://icma.org/
National Governors Association https://www.nga.org/
National League of Cities http://nlc.org/
U.S. Conference of Mayors https://www.usmayors.org/