The States and Territories page of the USA.gov website provides links to the home pages of all 50 states, the District of Columbia, and U.S. territories and associated states.
From the same page, there are links to sites that offer lists of state agencies by topic, governors, legislators, and overall state and territorial directories.
Municode offers codes for cities and counties from across the nation. Browse the Code Library and select the appropriate state from the map or menu. From there, you can select different cities or counties.