Survey township in the context of Dominion Land Survey

A civil township is a widely used unit of local government in the United States that is subordinate to a county, most often in the northern and midwestern parts of the country. The term town is used in New England, New York, as well as Wisconsin to refer to the equivalent of the civil township in these states; Minnesota uses "town" officially but often uses it and "township" interchangeably. Specific responsibilities and the degree of autonomy vary in each state. Civil townships are distinct from survey townships, but in states that have both, the boundaries often coincide, especially in Indiana, Ohio, and Illinois, and may completely geographically subdivide a county. The U.S. Census Bureau classifies civil townships as minor civil divisions. Currently, there are 20 states with civil townships, including Indiana, Ohio, Illinois, Michigan, Iowa, Minnesota, Wisconsin, Missouri, Kansas, Nebraska, South Dakota, North Dakota, Pennsylvania, and West Virginia (in certain areas).

Township functions are generally overseen by a governing board (the name varies from state to state) and a clerk, trustee, or mayor (in New Jersey and the metro townships of Utah). Township officers frequently include justice of the peace, road commissioner, assessor, and constable, in addition to surveyor. In the 20th century, many townships also added a township administrator or supervisor to the officers as an executive for the board. In some cases, townships run local libraries, senior citizen services, youth services, disabled citizen services, and cemetery services, besides emergency assistance. In some states, a township and a municipality that is coterminous with that township may wholly or partially consolidate their operations.

In U.S. land surveying under the Public Land Survey System (PLSS), a section is an area nominally one square mile (2.6 square kilometers), containing 640 acres (260 hectares), with 36 sections making up one survey township on a rectangular grid.

The legal description of a tract of land under the PLSS includes the name of the state, name of the county, township number, range number, section number, and portion of a section. Sections are customarily surveyed into smaller squares by repeated halving and quartering. A quarter section is 160 acres (65 ha) and a "quarter-quarter section" is 40 acres (16 ha). In 1832 the smallest area of land that could be acquired was reduced to the 40-acre (16 ha) quarter-quarter section, and this size parcel became entrenched in American mythology. After the Civil War, freedmen (freed slaves) were reckoned to be self-sufficient with "40 acres and a mule," though they never received it. In the 20th century real estate developers preferred working with 40-acre (16 ha) parcels. The phrases "front 40" and "back 40," referring to farm fields, indicate the front and back quarter-quarter sections of land.