This series has been divided into seven subseries to reflect Woodruff's diverse business and personal correspondence. The first subseries, law, consists primarily of correspondence from his law clients, for whom he worked in many cases as a debt collector, as well as from those he dunned for money. The second subseries represents his correspondence as postmaster of Litchfield. In addition to routine postal office business, including scheduling mail deliveries, inquiring about potential postal employees, and reporting misdirected mail, the collection also contains advertisements sent by individuals who wished to use the post office as a way to disseminate information about their products. One printed letter, from D. D. Addision, for example, advertises his expertise in pension claims and asks the postmaster to spread word about his business. Other correspondence reveals the postmaster's role in providing general information about the town and its community: one letters asks for information about law institutions in Litchfield, and another asks for information about Henry Wattles, who disappeared from Bridgeport after falling into debt. The third subseries represents Woodruff's interest in politics. Many of the letters in this subseries concern Woodruff's own election bids, discussing his possible candidacy and reporting on local election returns. The correspondence reveals much about politics and the election process; one letter from Wells Beardsley complains about "the gratuitous distribution of wine" among the electors on election day and asks Woodruff to examine whether it constitutes a breach of election law; another from Grun Kendrick apologizes for having given offense to Woodruff during a political debate; and many discuss the Whig and Democrat rivalry. The fourth subseries contains Woodruff's correspondence concerning financial investments, primarily in railroad companies. They include discussions about the price of bonds, purchase of shares, and dividends, and provide insight into the economic conditions and practices of the period. The sixth subseries contains Woodruff's personal correspondence. Early letters reveal Woodruff's social interactions with his Yale College acquaintances and his courtship of Henrietta Sophronia (Seymour) Woodruff, while later letters primarily consist of correspondence with his brothers Lewis and Reuben, which discuss Lewis's dissatisfaction with his law career in New York; Reuben's attempts to establish himself as a physician; news of their travels; and family matters.

Each of these subseries is arranged alphabetically by correspondent. The seventh subseries, which consists of Woodruff's correspondence to others, is arranged chronologically.