Hamilton Township, one of eleven in Warren County, Ohio, is in the south central portion of the county. The 2000 census found 9,630 people there, up significantly from the 5,900 in 1990. It is the fastest growing area of Warren County and is about 36 square miles (93 km²) in area. It is named for Alexander Hamilton.
Hamilton Township is bounded on the west and north by the Little Miami River (to the west is Deerfield Township and to the north is Union Township); to the east by Salem and Harlan Townships; and to the south by the Clermont County townships of Goshen and Miami .
It was one of the four original townships of Warren County, created on May 10, 1803, when the county was just nine days old. It originally encompassed all of the present Hamilton Township, plus the portion of Salem Township to the south of the Little Miami, all of Harlan Township, and most of Washington Township. On June 24, 1813, the eastern part of the township was sepearated by drawing a line south from the mouth of Todd's Fork on the Little Miami. The entirety of the township is in the Virginia Military District and was surveyed under the metes and bounds system.
The township is governed by a three-member board of trustees, who are elected in November of odd-numbered years to a four-year term beginning on the following January 1. Two are elected in the year after the presidential election and one is elected in the year before it. There is also an elected township clerk, who serves a four-year term beginning on April 1 of the year after the election, which is held in November of the year before the presidential election. Vacancies in the clerkship or on the board of trustees are filled by the remaining trustees.
The village of Maineville is near the center of the township. Parts of the township have been annexed by South Lebanon in the north and Loveland in the south. The communities of Zoar, Cozzadale, Murdock, Hopkinsville, Dallasburg, and Fosters are located here.
Most of the township is in the Little Miami Local School District, but parts are in the Loveland City, Kings Local, and Goshen Local School Districts. The township is primarily served by the Little Miami and South Lebanon telephone exchanges, but parts lie in the Morrow and Butlerville exchanges. Mail is delivered through the Maineville, Loveland, Goshen, South Lebanon, and Morrow post offices.
The major roads are US Route 22/Ohio 3, also known as the 3C Highway and originally known as the Cincinnati, Montgomery, and Hopkinsville pike. The Marietta and Cincinnati Railroad, which was absorbed by the Baltimore and Ohio Railroad, ran through the southeast corner of the township, while the Little Miami Road followed the Little Miami River through the township. (This is now the Little Miami Bike Trail.)
- Elva R. Adams. Warren County Revisited. [Lebanon, Ohio]: Warren County Historical Society, 1989.
- Robert L. Black. The Little Miami Railroad. Cincinnati: n.p., 1940.
- Robert Brenner. Maineville, Ohio, History: 100 Years as an Incorporated Town, 1850-1950. Cincinnati: John S. Swift, 1950.
- The Centennial Atlas of Warren County, Ohio. Lebanon, Ohio: The Centennial Atlas Association, 1903.
- Josiah Morrow. The History of Warren County, Ohio. Chicago: W.H. Beers, 1883. (Reprinted several times)
- Ohio Atlas & Gazetteer. 6th ed. Yarmouth, Maine: DeLorme, 2001. ISBN 0899332811
- Thomas D. Schiffer. Peters & King: The Birth & Evolution of the Peters Cartridge Co. & the King Powder Co. Iola, Wisconsin: Krause Publications, 2002. ISBN 087349363X
- William E. Smith. History of Southwestern Ohio: The Miami Valleys. New York: Lewis Historical Publishing, 1964. 3 vols.
- Warren County Engineer's Office. Official Highway Map 2003. Lebanon, Ohio: The Office, 2003.