The Ohio Company of Associates (which should not be confused with the Ohio Company formed about 1850) was formed at the Bunch of Grapes Tavern in Boston on March 1, 1786. It was based on an idea of General Rufus Putnam and others, that veterans of the Revolution would pool their resources in an association that would purchase land in Ohio. Shares were $1,000 each, and land purchase would be under the terms of the Ordinance of 1785.

In October 1787 the company received a contract from Congress for several million acres in Ohio, and an advance party went down the Ohio and established a settlement later known as Marietta. John May was one of the company agents, and arrived there a couple of months after the advance party in early 1788. These journals cover the period from his departure for Ohio until his return to Boston in December 1789. The editor has included a bibliography of manuscript sources and published sources.