Collinsville is an
unincorporated communityIn law, an unincorporated area is a region of land that is not a part of any municipality.To "incorporate" in this context means to form a municipal corporation, a city, town, or village with its own government. An unincorporated community is usually not subject to or taxed by a municipal government...
in southeastern
Milford TownshipMilford Township, one of thirteen townships in the county, is located in north-central Butler County, Ohio, United States, between Oxford and Middletown. The township, which contains the village of Somerville, had a population of 3,254 in 2000, up from 2,651 in 1990. Excluding Somerville, 2,960...
,
Butler CountyButler County is a county located in the state of Ohio, United States. As of 2010, the population was 368,130. Its county seat is Hamilton. It is named for General Richard Butler, who died in 1791 fighting Indians in northern Ohio. Butler's army marched out of Fort Hamilton, where the city of...
,
OhioOhio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...
,
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Although it is unincorporated, it has a
post officeA post office is a facility forming part of a postal system for the posting, receipt, sorting, handling, transmission or delivery of mail.Post offices offer mail-related services such as post office boxes, postage and packaging supplies...
, with the
ZIP codeZIP codes are a system of postal codes used by the United States Postal Service since 1963. The term ZIP, an acronym for Zone Improvement Plan, is properly written in capital letters and was chosen to suggest that the mail travels more efficiently, and therefore more quickly, when senders use the...
of 45004. It lies at the intersection of
U.S. Route 127U.S. Route 127 is a long north–south United States highway in the eastern half of the United States. The southern terminus of the route is at U.S. Route 27 in Chattanooga, Tennessee. The northern terminus is at Interstate 75 near Grayling, Michigan...
and
State Route 73State Route 73 is an east–west state highway in the southern portion of the U.S. state of Ohio. Its western terminus is on U.S. Route 27 in Oxford. State Route 73’s eastern terminus is in Portsmouth at U.S. Route 23; this is also the southern terminus of State Route 104, and the two state...
.