Armagh Public Library was founded in 1771 by Archbishop Richard Robinson. Built to the design of Thomas Cooley, the inscription over the public entrance in Greek means 'the healing place of the soul '. An Act of Parliament called 'An Act for settling and preserving the Publick Library in Armagh for ever' established the Library and its name - Armagh Public Library.

The nucleus of the collection is Archbishop Robinson's own library which contains 17th and 18th century books on theology, philosophy, classic and modern literature, voyages and travels, history, medicine and law.

There are many rare and valuable books such as John Gerson's 'De Praeceptis Decalogi' printed in Strasbourg, 1488; Sir Walter Raleigh's 'History of the World', 1614; Fynes Moryson's Travels, 1617 and Colgan's 'Acta Sanctorum Hiberniae', 1645. 'Gulliver’s Travels' by Jonathan Swift is regarded as a classic in world literature. A copy of Benjamin Motte’s first edition dated 28 October 1726 is kept in the Library. This copy carries amendments and markings in Swift’s own handwriting. There is also a varied collection of mediaeval and 17th and 18th century manuscripts, including the English compilation of the Annals of Clonmacnoise by Connell McGeoghegan, 1627 and the Armagh Corporation Books, 1731 to 1840.

In 2001 the Library received museum status in recognition of its role in the safe-keeping of a wider range of collections, such as Robinson's large collection of engravings known as the 'Rokeby Collection', with examples from the work of Piranesi, Hogarth and Bartolozzi. It houses many Irish artefacts collected by Archbishop Marcus Gervais Beresford during his lifetime. There are other items on view including the Silver Maces presented to Armagh when it became a city for the first time in 1656 and the only foreign flag ever captured on the island of Ireland.

Although an independent foundation and under the control of a Board of Governors and Guardians, the Library has always had the closest links with the Church of Ireland.