Historic estate and coastal plain beside Derbyhaven and Castletown Bay, now occupied in part by the Isle of Man Airport.

Ronaldsway appears in older sources as Rainsway, Ronaldsway, Rognvald's Vagr, Rognalwath, Rannesway and Ramsway. One nineteenth-century note identified the name with Reginald's Bay and described the anchorage as formerly the most important harbour on the Island because of its proximity to Castletown.

The surrounding ground was the scene of several medieval conflicts. In 1250 John Dugal-son, who had declared himself King of the Isles, was defeated there by the Manx. On 8 October 1270 a Scottish force under John Comyn and Alexander Stewart landed at Derbyhaven. The Manx resisted them on the field of Ronaldsway and were defeated with the loss of their leader Ivar and, according to the traditional account, 686 of their chief men.

In 1316 Richard de Mandeville landed at Ronaldsway with Irish followers. They advanced towards South Barrule, defeated the Manx and spent about a month plundering the Island before returning to their ships with their booty.

The bay was also the scene of an attempted attack on James Stanley, seventh Earl of Derby, in 1650. As he returned in a boat from visiting a Parliamentary vessel, a piece of ordnance loaded with shot was fired at him. Colonel Snaid, Colonel Richard Weston and Philip Lucas, the boat's master, were killed, while Derby escaped.

Ronaldsway later became closely associated with the Christian family. Deemster Ewan Christian held the estate, and his son William Christian, Illiam Dhone, was described in a later ballad as possessing a house like a king's, with woodlands, springs and a garden compared to Eden. A dispute over the estate had already reached James Stanley in 1643, when a petition alleged that an infant had a claim to Ronaldsway.

William Christian was executed at nearby Hango Hill in January 1663. The estate continued in the hands of representatives of the same family afterwards.