MARIETTA, a city of the United States, the capital of Washington county, Ohio, lies on the right bank of the Ohio, at the mouth of the Muskingum, 85 miles south-east of Columbus, and is the eastern terminus of the Marietta and Cincinnati Railroad, and the southern terminus of the Cleveland and Marietta Railroad. The surrounding country being rich in petroleum, iron, and coal, the city has become the seat of no inconsiderable industry in the shape of oil-works, iron foundries, and machine-shops, a rolling mill, tanneries, and carriage, car, bucket, aud chair factories. Marietta College, chartered in 1835, and maintained by voluntary endowment and subscription, is a flourishing institution, with eight instructors and a library of 25,000 volumes, occupying a fine group of buildings in the midst of extensive grounds. The population of the city has risen from 3175 in 1850 to 5444 in 1880. At the latter date the township, which includes the village of Harmar (1572), contained 8830 persons.

Marietta, founded in 1788 by General Putnam, and named in honour of Marie Antoinette, is the oldest town in Ohio. It is built on the site of a remarkable group of prehistoric monuments, the largest of which are two enclosures, respectively 40 and 20 acres in extent, formed by walls from 20 to 30 feet broad at the base, and still in some places 5 and 6 feet high. See Squier and Davis, Ancient Monuments of the Mississippi Valley.