Delphos is a city in Allen and Van Wert counties in the U.S. state of Ohio approximately 14 mi (23 km) northwest of Lima and 13 mi (21 km) east of Van Wert.

The Allen County portion of Delphos is part of the Lima Metropolitan Statistical Area, while the Van Wert County portion is part of the Van Wert Micropolitan Statistical Area.

Delphos had its start in the early 1850s with the merger of neighboring rival towns.

The first settlers to Delphos were mainly construction workers attracted by the work being done on the Canal.

[8] The Canal was crucial to the economic development of the city in the 19th century, since it positioned Delphos as a center of regional trade.

By 1879, more than 100 factories located in Delphos produced goods for national and international trade.

[8] Three Delphos buildings are listed on the National Register of Historic Places: the Marks-Family House and St. John's Catholic Church on the Allen County side of the city, and the Bredeick-Lang House on the Van Wert County side (see Gallery below).

29.9% of all households were made up of individuals, and 13.8% had someone living alone who was 65 years of age or older.

Stadium Park is home to a football field where the Delphos Jefferson Wildcats and the St. Johns Blue Jays play.

Both the high school and elementary buildings are located in Allen County.