There is no definitive explanation for the origin of the name "Maine", but the most likely origin is that the name was given by early explorers after the former province of Maine in France. Whatever the origin, the name was fixed for English settlers in 1665 when the English King's Commissioners ordered that the "Province of Maine" be entered from then on in official records. The state legislature in 2001 adopted a resolution establishing Franco-American Day, which stated that the state was named after the former French province of Maine.
Other theories mention earlier places with similar names, or claim it is a nautical reference to the mainland. Attempts to uncover the history of the name of Maine began with James Sullivan's 1795 "History of the District of Maine". He made the unsubstantiated claim that the Province of Maine was a compliment to the queen of Charles I, Henrietta Maria, who once "owned" the Province of Maine in France. This was quoted by Maine historians until the 1845 biography of that queen by Agnes Strickland established that she had no connection to the Province of Maine in France; further, King Charles I married Henrietta Maria in 1625, three years after the name Maine first appeared on the charter. A new theory, put forward by Carol B. Smith Fisher in 2002, is that Sir Ferdinando Gorges chose the name in 1622 to honor the village where his ancestors first lived in England, rather than the province in France. "MAINE" appears in the Domesday Book of 1086 in reference to the county of Dorset, which is today Broadmayne, just southeast of Dorchester.
The view generally held among British place name scholars is that Mayne in Dorset is Brythonic, corresponding to modern Welsh "maen", plural "main" or "meini". Some early spellings are: MAINE 1086, MEINE 1200, MEINES 1204, MAYNE 1236. Today the village is known as Broadmayne, which is primitive Welsh or Brythonic, "main" meaning rock or stone, considered a reference to the many large sarsen stones still present around Little Mayne farm, half a mile northeast of Broadmayne village.
The first known record of the name appears in an August 10, 1622 land charter to Sir Ferdinando Gorges and Captain John Mason, English Royal Navy veterans, who were granted a large tract in present-day Maine that Mason and Gorges "intend to name the Province of Maine". Mason had served with the Royal Navy in the Orkney Islands, where the chief island is called Mainland, a possible name derivation for these English sailors. In 1623, the English naval captain Christopher Levett, exploring the New England coast, wrote: "The first place I set my foote upon in New England was the Isle of Shoals, being Ilands [sic] in the sea, above two Leagues from the Mayne." Initially, several tracts along the coast of New England were referred to as Main or Maine (cf. the Spanish Main). A reconfirmed and enhanced April 3, 1639, charter, from England's King Charles I, gave Sir Ferdinando Gorges increased powers over his new province and stated that it "shall forever hereafter, be called and named the PROVINCE OR COUNTIE OF MAINE, and not by any other name or names whatsoever..." Maine is the only U.S. state whose name has exactly one syllable.