National Association of Counties
Offers state by state lookup of county by city name as well as clickable state maps showing names of counties with links to geographic and demographic information for each county. Search county codes and ordinances by state, subject, or keyword.

National Association of Counties: Cities Search
Search by city name, state or county to find localities within a certain region.

National Association of Counties: Map
Clickable map of US states linking to information about the counties within a state.

Why Do You Think They Call Them Counties?
Site which allows users to track the U.S. counties they have visited. Includes maps, trivia, and quizzes about counties.

County Highpointers Association
Provides information for and encourages individuals to visit the highest points in every United States county. Contents include maps and charts, trip planning literature and links, elevation rules, calculators, and high point listings.

Extra Miler Club
Organization of road trippers who share the goal of visiting every county in the United States. Membership information and directory provided, as well as meeting announcement, travel links, and county FAQ.

County Hunter Dot Com
A resource for amateur (ham) radio operators trying to make contact with individuals in every U.S. county. Site describes events, awards, and featured county hunters, and provides calendar, directory, photographs, discussion forums, and guides.