In Michigan, a township is a subdivision of a county consisting of 36 sections arranged in a 6 by 6 square, measuring 6 miles by 6 miles (see this page, image 5 of 1955 Adams Twp sections). These measured-out units are referred to as “Congressional townships” because they are created by an act of the state.

A general law township is the area under the management of a local governing body with its own elected officials, and may cover more or less than 36 square miles.  A charter township is a special classification created by the 1947 Michigan Legislature to provide greater protection against annexation by a city. As of  2026, there are 143-146 Michigan townships considered to be chartered.

Due to natural formations, waterways and coastlines, some counties are not actual rectangles and may end up being quite small.

Congressional townships much less than 36 may be under the jurisdiction of a county next to it, coming under the governance of a “political township.” Arenac County has four township comprised of less than 36 square miles– Lincoln, Sims, Standish and Whitney–but have existed as political townships of themselves, with their own governmental units.

There are two types of townships in Michigan—general law and charter townships. Charter township status is a special township classification created by the Michigan Legislature in 1947 to provide additional powers and streamlined administration for governing a growing community. A primary motivation for townships to adopt the charter form is to provide greater protection against annexation by a city. Currently, 146 Michigan townships have opted to become charter townships.

The US Public Land Survey System (USPLSS) recognizes principal meridians as the north-south lines used for surveying large areas of land. These are north-south lines marks used to divide townships between east and west sections. Baselines run east-west and are used as north and south references for defining sections. (Michigan is the only state with two baselines.)

The basic unit the USPLSS of the system is the “section” within a township.  One section is–in theory–one piece of land that measures 1 mile by 1 mile square, each containing 640 acres. Within each section, property may be sold as half, quarter or one-sixteenth (“quarter of a quarter”) quarter.

Plat maps (also referred to as cadastral maps) carry letter and number combination notations that describe the location of property within the township:

• R – range lines; north- south lines marking boundaries (measuring E-W of a Principal Meridian
• T – township lines; east-west lines marking township boundaries
• Number: Section numbers begin at the northeast-most section as #1. Numbering proceeds west to #6, then it drops down (south) to run the opposite direction (west) along the bottom of the previous. This switch-back continues until it ends at the south-seat corner as #36.

Translating land descriptions to maps can be frustrating for those new to the concept. If you are following family history through land purchases and sales, you find it helpful to read some of the articles recommended in the land survey systems section below.

Another type of cadastral map useful for genealogists is a Sanborn Fire Insurance, drawn up of an urban area. Noting blocks and street numbers, fire insurance maps show the size, shape, and construction of commercial buildings, factories and homes with details about fire walls, windows, doors, roof types, sprinkler and water systems, and fire hydrants. If you have a family history story about a fire, a Sanborn map could give clues to how and why the fire was responded to as it was. Library of Congress maps for Arenac County cover only Standish, for 1895, 1909, 1904 and 1924. (See Sanborn Maps below)

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