In 1717, a collection of law books belonging to the provincial government formed the first state library collection. After the State House was built in 1816, a room was set aside for the library and, for a time, the Secretary of State served as the State Librarian. In 1895, a separate building was constructed to house the State Library and the New Hampshire supreme court.
The State Library created a Law Division in 1943. The Law Division served as the law library for many years. When the current supreme court building was constructed in 1970, the Law Division moved with the New Hampshire supreme court to the new building.
In 1994, the legislature transferred administration of the Law Division to the Judicial Branch, and created the New Hampshire Law Library. By statute (N.H. Rev. Stat. Ann. 490:25) the law library is available for the use of the supreme court and other members of the judiciary, the attorney general, members of the legislature, officials of state government, the legal profession of New Hampshire, and the people of the state.
In 2007, the legislature named the law library in honor of John W. King (2007 N.H. Laws 126). Chief Justice King served as minority leader of the New Hampshire house of representatives, as governor of New Hampshire, as associate justice of the New Hampshire superior court, as associate justice of the New Hampshire supreme court, and as chief justice of the New Hampshire supreme court. Chief Justice King's portrait hangs in the law library.