Trenton is a city in northeastern Butler County, Ohio, United States, west of Middletown.

Trenton was originally called Bloomfield, and under the latter name was platted in 1815.

In 1831, it was discovered that there was already a Bloomfield post office in Ohio, and so the town was renamed after the state capital of New Jersey at Trenton.

[6] Trenton is located on the west bank of the Great Miami River.

According to the United States Census Bureau, the city has a total area of 4.56 square miles (11.81 km2), all land.

17.1% of all households were made up of individuals, and 6.4% had someone living alone who was 65 years of age or older.

17.1% of all households were made up of individuals, and 6.8% had someone living alone who was 65 years of age or older.