In 1854, Phineas Swift, a New Yorker, became the first permanent settler. A post office was established on September 29, 1862, with Joshua V. Noah as the first postmaster. The community was named for the township, which in turn was named for Sidney, Ohio, the home of some of its early settlers. The Sidney post office, with ZIP code 48885, serves the central part of the township, as well as part of Montcalm Township to the west.
Historical picture of Sidney Michigan in its early days.