In 1843, astronomer Ormsby Mitchell of Cincinnati College (now the University of Cincinnati) laid out plans for a new telescope and observatory in Cincinnati. After a benefactor donated four acres of land on Mt Ida, near present-day Eden Park, Mitchell raised a total of $7,000 from private citizens and obtained an 11-inch refracting telescope from the Merz Und Mahler Company in Germany (at that time there were no telescope makers in the US). It was the largest refracting telescope in the US and the third-largest in the world. The Observatory was dedicated by former President John Quincy Adams, and in his honor the site was renamed Mt Adams.
By 1871, the Mt Adams site was becoming too obscured by the dust and smoke from the city, so the telescope was dismantled and moved to a new site on Mt Lookout, where it remains today. In 1904, it was decided that the 11-inch telescope was becoming obsolete, so the Observatory obtained a new 16-inch refractor made in the US by Alvan Clark and Sons. The 11-inch telescope was moved to a new (but smaller) domed building next door, and the new 16-inch refractor was placed in the old building. They both remain today.
Ormsby Mitchel became a General in the Union Army during the Civil War and died from yellow fever while on duty in South Carolina. The Observatory continued to carry out scientific studies until the 1970s. For a time, the observatory hosted the International Astronomical Union Minor Planet Center, which keeps track of asteroids.
In the 1980s, the observatory and its telescopes were restored and opened as an educational center for the public. Today there are guided tours, and members of the public are invited to view the planets and other solar system objects at night.
Some photos from a tour.