unincorporated community
An unincorporated area is a parcel of land that is not governed by a local general-purpose municipal corporation. (At p. 178.) They may be governed or serviced by an encompassing unit (such as a county) or another branch of the state (such as th ...
U.S. state
In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its so ...
of
Indiana
Indiana ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Michigan to the northwest, Michigan to the north and northeast, Ohio to the east, the Ohio River and Kentucky to the s ...
. Petroleum has an approximate population of 100.
History
Petroleum was platted in 1894, and is so named because it was laid out in an oil field. The post office at Petroleum has been in operation since 1894.