The Ohio Company, founded in 1747, represented the trading and land prospecting interests of a handful of Virginia planters. Thomas Lee was appointed president, Nathaniel Chapman served as treasurer, and John Mercer was both secretary and general counsel. In that year, John Mercer’s son, George Mercer, was appointed the company’s representative in England. In 1748 the British Crown approved a land grant to the company to be administered by the Colony of Virginia. The grant covered the Ohio territory, a colloquial term for what is now modern day West Virginia, much of Ohio, western Pennsylvania and parts of Maryland. Governor Robert Dinwiddie, a member of the company, required that the company develop trade with the Indians, erect forts, and settle one hundred families to secure the grant. The company employed frontiersman Christopher Gist to survey the area of the grant in 1750. Two years later, Iroquois leaders signed a treaty at Loggstown, Pennsylvania, a large Native American settlement on the Ohio River near preswent-day Ambridge, Pa. Gist was the representative of the Ohio Company and Colonel Joshua Fry represented the Colony of Virginia at the negotiations. The Ohio territory was also claimed by the French, who began erecting forts in the Ohio Valley in reaction to the Treaty at Loggstown and other factors. By the beginning of the French and Indian War in 1754, the Ohio Company’s efforts were largely stymied, despite its continued existence until its formal dissolution in 1779. Other members of the company included Virginians George Mason, brothers Lawrence, Augustine, and George Washington, Governor Robert Dinwiddie, and British merchant John Hanbury.
The Ohio Company and Pennsylvania frontier history were of great interest to a handful of late-nineteenth-century American scholars, among them William M. Darlington. According to a letter in the collection case file dated September 1884 and written by William R. Mercer, a descendant of George Mercer, to Lyman C. Draper of the Wisconsin State Historical Society, "...the whole of Capt. Christopher Gists diary in the hand writing of one of the Early members of my family -- was sold some years ago in New York with other valuable papers in relation to the Ohio Company to Mr. William Darlington of Pittsburgh Penn who no doubt still has them, he being as I understand Engaged in writing a history of the Ohio Co." This evidence suggests that the Gist journals in this collection are not the original journals penned by Gist, but represent a copy created by a Mercer relative, who is believed to be John Mercer. Further, writing to a researcher in October 1938, Lois Mulkearn, the Darlington Memorial Librarian, said that "The Darlington Library does not contain any maps or other manuscript material by Christopher Gist, but does hold a manuscript copy of Gist's journals made by one other than Christopher Gist himself. You probably know that the greater part of the records of the Ohio company were destroyed by fire at the time of the Civil War. The remaining volumes are in the Manuscript Department of the Pennsylvania Historical Society at Philadelphia." This supports the collection provenance as described in the Custodial History (see below).
Darlington indeed did compile a history of the Ohio Company in the form of the publication of
Christopher Gist's Journals published posthumously in 1893. While Darlington's publication contains Gist's journal entries, the book largely contains Darlington's explanatory notes on the entries, such as where particular camps were located and biographical sketches of important figures from Gist's journals. Multiple editions of Gist's journals have been published, the earliest as an appendix to Thomas Pownall’s 1776
A Topographical Description of North America. In the 1950s, there was a major upsurge of interest in the frontier history of the eastern United States. In the 1940s and 1950s, Lois Mulkearn, the first Darlington Memorial Librarian, took up an extensive study of the Ohio Company papers collected by William Darlington. Mulkearn wrote the
George Mercer Papers, the authoritative volume on the Ohio Company Papers, particularly the
Case of the Ohio Company compiled by George Mercer.