Peter Force (November 26, 1790 – January 23, 1868) was an American politician, newspaper editor, printer, archivist, and early American historian. He was twice elected the twelfth Mayor of Washington D.C. During his lifetime he amassed an invaluable and vast collection of books, manuscripts, original maps and other archival material from statesmen, and American and British military officers of the American Revolution. Force's collection is considered to be among the most extensive. Force served in the Washington militia as a lieutenant during the War of 1812. Politically, he was a member of the Whig Party, and supporter of John Quincy Adams. He is mostly noted for editing and publishing a massive collection of historical documents, books and maps in several volumes involving the American colonies and the American Revolution which was ultimately purchased by the Library of Congress for a large sum. Force founded a political journal and other publications and was president of a premier national science society, and the Typographical Society which was largely charged with the task of communicating political affairs to the general public. Force served on the committee that approved the Geographical Department for the Library of Congress. During the international political unrest caused by the American Civil War, Force was sent to Europe by the Lincoln Administration to stabilize diplomatic relations with France and England.
In 1812 Force became a member of the New York Typographical Society, which was the city's printer trade union at the time. He was initiated at its general meeting on February 1, 1812. He was elected a director on December 5, 1812, and at age twenty-two was chosen president on July 3, 1813, with his re-election following in 1814 and 1815. In 1815, Force's employer secured a contract for the printing of Congress, and moved to Washington, D.C., and Peter Force, at age twenty-five, followed and also became a resident and a printer in that city. Soon he formed a partnership with Davis working as the foreman and public printer in the congressional printing plant, which at the time was quite small, having only four single-pull, wooden hand presses, which were sufficient to do all the work of the Government in 1816. In that same year he joined the Columbia Typographical Society and in 1826 became its first "free member". When Davis withdrew from the partnership Force formed other partnerships, of which he was the master mind.
Early in his career in Washington Force attracted the attention of distinguished statesmen, and he was a leading character in the city throughout his life. From 1820 to 1836, with a three-year interval involved in politics, he published the National Calendar, which later became the National Calendar and Annals of the United States.
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During the 1820s, Force was a member of the prestigious society, Columbian Institute for the Promotion of Arts and Sciences and served as the president.
During his lifetime he was also a member of the Smithsonian Institution and the United States Naval Observatory, and played a major role in organizing the American Historical Society, in Washington in 1836. On August 22, 1822, Force was granted US Patent 3573X for a method of color printing. He also founded, published, and wrote in the National Journal (1823–1830) and would later donate a stone to the Washington Monument. After vigorously supporting John Quincy Adams' election to the presidency in 1824,
Up until the early 1850s, the Library of Congress lacked a geographical department and an adequate collection of maps for an institution of its size and station. Lieutenant Edward B. Hunt of the U.S. Army formulated a plan and proposed a resolution for such a department and appointed a committee to review the proposal. Force was on the committee that passed that resolution in 1856. and Force were co-publishers of Force's American Archives. Force's lifelong desire to contribute to the Library of Congress finally came to fruition in 1867 when through an act of Congress it purchased his collection of original documents for $100,000,
During his years of pursuing and buying archival material Force carried off prizes at auctions which the other competitors were not knowledgeable of. Force traveled about the eastern seaboard of the United States "ransacking" the book-shops and attending book auctions from Boston to Charleston in his tireless search for rare volumes. On one such occasion he was a bidder against the Library of Congress for a sizable and valuable library of bound pamphlets, the property of an early collector, who had consigned them to an auction house in Philadelphia. On another occasion while in Boston Force acquired from an antiquarian bookseller the only collection of Boston Revolutionary newspapers which were offered for sale in the last twenty-five years. He was soon reproached by some visitors from New England and admonished for depriving New England of its archival treasure. He rebuffed them replying, "Why didn't you buy them yourselves, then?" Force was relentless in his efforts to acquire complete and unbroken collections of all the Washington newspapers he could lay his hands on. After some thirty years he had amassed a collection which nearly filled the basement in his home. Into his elder years Force often visited the War Department, approaching various Army officers he knew in his quest for archival material. His collection of the printed "Army orders" from the War Department was considered "a miracle of completeness".
thumb|left|upright=0.8|Peter Force, book cover, 1886, Origin, Settlement and Progress
In 1867 the Library of Congress and a joint Committee of Congress was formed for the purpose of examining the extensive assortment of archival material in the Peter Force library. Because of its enormous size, totaling approximately 150,000 items, it was necessary for the committee to enter closely into details, and to devote much time and assiduous effort to the task of assessing Force's library. The committee spent at least two to three hours per day, for a two month period, in the examination of every document, manuscript, book, map, etc, that passed through their hands. To help simplify matters the contents of the Force library were categorized into seven basic classes.