This volume contains a list of the field staff, commissioned officers, non-commissioned officers, and privates of a provincial regiment commanded by John Thomas.

This letterbook contains letters to John Thomas, as well as drafts of letters from John Thomas to various individuals. Most of Thomas's correspondents are family members, primarily his brother Anthony Thomas, his father John Thomas (1683-1770), and Nathaniel Ray Thomas. Among the other correspondents are Simon Tufts, Cotton Tufts, Joseph Goldthwaite, and Crocker Sampson. John Thomas's diary, located at 171.1.9.18, describes a brief trip to Connecticut, 27 Sep.-9 Oct. 1752.

Also included in this subseries are papers of other family members, including Hannah Thomas and John Thomas, Jr. (1766-1853), and correspondence of Thomas's grandson John Thomas III (b. 1793), primarily with Joseph Sampson, Augustus Thomas, and John Thomas, Jr. Letters between Sampson and John Thomas III relate to their time as students at Brown University.

Note: This volume is identified on the microfilm as "Letterbook, 1693-1835."

The bulk of this letterbook consists of letters from John Thomas to his wife Hannah Thomas, written while he was serving as commander at Roxbury during the Siege of Boston, 1775-1776. The volume also contains a few letters from Hannah Thomas to John Thomas, as well as some financial and legal papers.

Note: This volume is identified on the microfilm as "Letterbook, 1775-1838."

This letterbook primarily consists of letters to John Thomas from a variety of significant contemporary figures, including Jotham Gay, Benjamin Lincoln, Jeffery and William Amherst, Artemas Ward, James Warren, Josiah Quincy, George Washington, Charles Lee, Horatio Gates, Theophilus Cotton, Mercy Otis Warren, John Adams, Philip Schuyler, Benedict Arnold, Baron de Woedtke, and many others. Also included are a few letters from John Thomas to various individuals.

This subseries also contains Thomas's military commissions from William Shirley (1746 and 1755), Thomas Pownall (1759 and 1760), Thomas Hutchinson (1770), Joseph Warren (1775), and John Hancock (1775 and 1776), as well as papers related to courts-martial, 1775.

Note: This volume is identified on the microfilm as "Letterbook, 1755-1776."

This letterbook contains John Thomas's incoming and outgoing correspondence with a variety of individuals, including Miles Whitworth, Benjamin Lincoln, Isaac Lothrop, John Brown, John Adams, Mercy Otis Warren, Jotham Gay, Jeremiah Hall, James Hamilton, Abel Keen, Job Winslow, and many others. Included are letters to and from many of the same correspondents represented in Series III.C. Letterbook, 1713-1844.

This subseries also contains a large number of military papers, including orders and returns from Thomas's service in the French and Indian War (1755-1760); billeting rolls of companies in John Thomas's regiment at Castle William (1759); and papers related to the courts-martial of David Davis (1775) and Jabez Palmer, Moses Snell, John Downing, and John Fling (1759).

Note: This volume is identified on the microfilm as "Letterbook, 1747-1776."