When, in the year 1862, the call of the Government was made for men to serve nine months, the quota of Massachusetts was seventeen regiments and one battery; and the Sixth, for the second time, gave the first response. It reported in Washington, ready for duty, before any other regiment arrived. It preserved the same organization, with such changes of officers and companies as such times would inevitably produce. Seven companies were the same, namely, A (Lowell), B (Groton), C and D (Lowell), E (Acton), H (Lowell), and I (Lawrence). Company F (Lawrence) was partially recruited for the present campaign, and then was consolidated with company I. The place of the old company F was filled by a new company from Cambridge; and the old company G was supplied by company G from Lowell; and company K, a new company from Chelmsford and the neighboring towns, completed the ten. With these exceptions, the regimental organization, with the old books and papers, was identical with that of the three months, and was, in fact, the old State organization preserved and continued, with about seventy-five officers and men, among whom during the campaign, were twenty-seven commissioned officers, who had served during the three months; so that the Sixth of the "Nine Months" campaign was the "Old Sixth" of the "Three Months," and of Baltimore, and of the Nineteenth of April. The history of the original seven companies having been given in the account of the three months campaign, it remains to trace the remaining three. Company F was recruited expressly for the nine months campaign, and was mustered in last of all the companies. Companies G and K were also recruited for the campaign, and have no previous history; and these three new companies sustained themselves throughout in a manner fully worthy the place they occupied in the regiment. Of the privates, 324 were born in Massachusetts; while 112 were born in Maine, 107 in New Hampshire, 32 in Vermont; and 168 were born in foreign countries, England, Ireland, France, Canada, etc. 319 followed the different mechanical trades, giving some to every one ever heard of; 132 were farmers, 50 were clerks, and 141 worked at various departments of manufacturing, mostly in cotton or woollen factories. There were 10 sailors, several theological and other students, 1 clergyman, 1 physician, and printers, teamsters, teachers, apothecaries, and one or more following almost every branch of business known in New England, with the exception of the legal profession. There was not a lawyer in the regiment, a remarkable fact.

Source: "Historical Sketch of the Old Sixth Regiment of Massachusetts Volunteers during its Three Campaigns" by John H. Hanson, Chaplain of the 6^th Regiment, published in 1866. This book is online at Archive.org.