The Board of Supervisors is the body governing counties in Arizona, California, Iowa, Mississippi, Virginia, and Wisconsin. In other states it may be called the County Council. Similar to city councils, the board has legislative, executive, and quasi-judicial powers. Originally, a county was the land under the jurisdiction of a count (in Great Britain, an earl, though the original earldoms covered larger areas) by reason of that office. ... Official language(s) None Capital Largest city Phoenix Phoenix Area  Ranked 6th  - Total 113,998 sq mi  (295,254 km²)  - Width 310 miles (500 km)  - Length 400 miles (645 km)  - % water 0. ... Official language(s) English Capital Largest city Sacramento Los Angeles Area  Ranked 3rd  - Total 158,302 sq. ... Official language(s) English Capital Des Moines Largest city Des Moines Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 26th 145,743 km² 320 km 500 km 0. ... Official language(s) English Capital Jackson Largest city Jackson Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 32nd 125,443 km² 275 km 545 km 3 30°13N to 35°N 88°7W to 91°41W Population  - Total (2000)  - Density Ranked 31st 2,697,243 23. ... Official language(s) English Capital Largest city Richmond Virginia Beach Area  Ranked 35th  - Total 42,793 sq. ... Official language(s) None Capital Largest city Madison Milwaukee Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 23rd 169,790 km² 420 km 500 km 17 42°30N to 47°3N 86°49W to 92°54W Population  - Total (2000)  - Density Ranked 18th 5,453,896 38. ... A city council is the most common style of legislative government in a city or town. ...

Under a board's legislative powers, the supervisors have the ability to pass and repeal laws, generally called ordinances like in cities. Depending on the state, and the subject matter of the law, these laws may apply to the entire county or only to unincorporated areas not under jurisdiction by a city. In addition, a board approves the county's budget, and may set tax rates or approve land use plans. In United States law, a region of land is unincorporated if it is not a part of any municipality. ...

In some states, including Michigan until 1968, or in some New York counties until recently, most county territory is divided into townships or towns, each one with a chief elected official titled "supervisor". The officeholder would have administrative authority in a township, while serving as that township's representative on the county board of supervisors. However, this system gave every township exactly one vote on the board of supervisors regardless of population, which meant small (usually rural) townships had disproportionate clout in county decision making. Cities also had elected or appointed supervisors on the county boards, but these generally didn't have administrative roles comparable to township supervisors. Official language(s) None (English, de-facto) Capital Largest city Lansing Detroit Area  Ranked 11th  - Total 102,384 sq. ... Official language(s) None, English de facto Capital Largest city Albany New York City Area  Ranked 27th  - Total 54,520 sq mi  (141,205 km²)  - Width 285 miles (455 km)  - Length 330 miles (530 km)  - % water 13. ...

Both Michigan and New York changed to single member districts for electing county boards, replacing the former board of supervisors. In Michigan, every county divided itself into equal population districts in 1968 to elect what were at first called "county supervisors", but (because of the confusion with the now separate township supervisors) were retitled as "county commissioners" in 1970. In New York, the new board members were called "county legislators" (and the body, the "county legislature"), but not every county adopted this system immediately. Those which retained the old boards of supervisors after the 1960s assigned each member a fractional vote based on the population represented.

Under a board's executive powers, the board controls county departments. Generally this is done under the aegis of a chief administrative officer or county executive. The power of the CAO or county executive to act independently depends on the composition of the board. Generally, like most city managers, the CAO or county executive has authority over the day to day operations of the county's departments. Many boards independently appoint department heads, while other boards may delegate that authority to the CAO or chief executive. Some departments may be elected separately by the electorate; however, the board still exerts some power over these department's budget. Despite the presence of a CAO or chief executive, it is not uncommon for an individual supervisor to meddle in the affairs of individual departments, like setting priorities for projects in one's district or independently requesting investigations of problems in a department. In some counties, the county executive is elected. In San Francisco, the county executive is called the mayor and has the same powers as any strong-city mayor. A chief administrative officer (or CAO) is a corporate officer responsible for management of the personnel of the corporation. ... A County Executive is the title assigned to a person hired to run the day to day operations of a county. ... The council-manager government is one of 2 main variations of representative municipal government (for contrast, also see Mayor-Council government). ... This page is a candidate for speedy deletion. ... A mayor (from the Latin māior, meaning larger,greater) is the politician who serves as chief executive official of some types of municipalities. ...

Under a board's quasi-judicial capacity, the board is the final arbiter of decisions made by commissions underneath a board. This generally involves land use planning issues. Urban, city, or town planning, deals with design of the built environment from the municipal and metropolitan perspective. ...