Since 1835 the city has been home to Marietta College, a private, nonsectarian liberal arts school with approximately 1,200 students.

Among them were more than one culture who built earthwork mounds, monuments which generally expressed their cosmology, often with links to astronomical events.

[7] Between 100 BC and AD 500, the Hopewell culture built the multi-earthwork complex on the terrace east of the Muskingum River near its mouth with the Ohio.

French explorers entered this area in the 18th century, and in 1749 buried numerous leaden plates to mark their claim to the Ohio Country (which they called the Illinois Territory, as they had more settlements near the Mississippi River.)

In 1770, the future U.S. president George Washington, then a surveyor, began exploring large tracts of land west of his native Virginia.

During the Revolutionary War, Washington told his friend General Rufus Putnam of the beauty he had seen in his travels through the Ohio Valley and of his ideas for settling the territory.

[9][10] After the American Revolutionary War, the U.S. sold or granted large tracts of land to stimulate development in this area.

[15] The site was on the east side of the Muskingum River, across from Fort Harmar, a military outpost built three years prior.

Bringing with them the first government sanctioned by the US for this area,[16] they established the first permanent United States settlement in the Northwest Territory.

The Americans named Marietta in honor of Marie Antoinette, the Queen of France, who had aided the colonies in their battle for independence from Great Britain.

The settlers immediately started construction of two forts: Campus Martius, whose former site is now occupied by the museum of the same name, and Picketed Point Stockade, at the confluence of the Muskingum and Ohio rivers.

The US signed the Treaty of Greenville (1795) with the Indigenous people, which secured the safety of settlers to leave the forts and develop their farms.

[22] Ohio University was founded earlier in Athens, on land reserved for public education under the Northwest Ordinance.

[8] As of 1900, the Mound Cemetery had the highest number of burials of Revolutionary War officers in the nation, indicating the nature of the generation that settled Marietta.

Artisans built oceangoing vessels and sailed them downriver to the Mississippi River and south to New Orleans and the Gulf of Mexico.

An iron mill, along with several foundries, provided rails for the growing railroad industry; the Marietta Chair Factory made furniture.

"[8] The walled, graded path, called by the settlers the Sacra Via, led from the largest enclosure to the lower river's edge.

[citation needed] In 1871, the Ohio Valley Railroad was formed and for the next two years built tracks going north for 103 miles.

[citation needed] The planned bridge from Parkersburg across the Ohio River to Belpre was finally built 1868–1870 by the B&O, as part of its main line from Baltimore to St. Louis, Missouri.

Oil booms in 1875 and 1910 made investors rich, who constructed numerous lavish houses in town, of which many still stand.

In 1925, he shared the Nobel Peace Prize, based on his work on the Dawes Plan and relieving an international crisis in 1923 related to German reparations after World War I.

From 1868 to 1870, the B & O Railroad built a bridge to connect Parkersburg, West Virginia and Belpre; and the National Road went further north through Zanesville.

After WWII passenger service decreased as the railroads restructured and the federal government invested in highway construction.

In 1937–1938, during the US celebration of the Northwest Territory, France gave a plaque to the city of Marietta, which was installed on the French monument, to commemorate these young men and their service.

In 1939, the Sons and Daughters of Pioneer Rivermen was established in Marietta during the Great Depression to celebrate the city's substantial river history and its people.

[30] The climate in this area is characterized by humid summers, cold winters, and evenly distributed precipitation throughout the year that can not be accurately predicted because of the amount of water in the Ohio Valley.

A Marietta Civil War Reenactment is held annually, and features Union and Confederate reenactors battling across the Muskingum River.

Interstate 77 runs east of Marietta connecting it to Cleveland, Ohio, to the north and Charleston, West Virginia, to the south.

The trail runs along the Ohio and Muskingum rivers and connects various points of interest throughout Marietta, including downtown and multiple parks.

Notable people on the List of early settlers of Marietta, Ohio include: Arthur St. Clair, Major General and Patriot in the revolutionary war, 9th President of the Continental Congress, he was the first governor of the Northwest Territory; Gen. Rufus Putnam, Gen. Benjamin Tupper, Gen. James Varnum, Gen. Samuel Holden Parsons, Commodore Abraham Whipple, Col. William Stacy, and Griffin Greene.