In what year was the Cincinnati Open founded?

The Cincinnati Open was founded in 1899.

The first edition began on September 18, 1899, making the event one of the oldest tennis tournaments in the United States still played in or near its original city. Its earliest competition was held at the Avondale Athletic Club.

The tournament was originally played on clay, described in contemporary reporting as crushed brick dust. It later moved through several Cincinnati-area locations before settling in Mason in 1979 and switching to hard courts.

The year 1901 is a related but different date: that was when the event adopted the name Tri-State Tennis Tournament. The tournament’s founding year remains 1899 despite its many later names and venue changes.