chief town, resort, parish, and the capital of Jersey, in the Channel Islands. The town lies along St. Aubin's Bay opposite a tidal island known as L'Islet (accessible by causeway at low tide), on the south side of Jersey Island. The town is named for St. Helier, a Frankish missionary who was reputedly martyred there in 555. The saint's memory is preserved in the Hermitage, a small 12th-century oratory on L'Islet, as well as in the Abbey (later Priory) of St. Helier, founded in the mid-12th century by Robert FitzHamon, of Gloucester.

The town originated as a fishing village that grew up beside the parish church, where from the 13th century the king's courts usually met and where markets were held. St. Helier became the seat of island government after Elizabeth Castle was built (1551–90) on L'Islet. This castle was the refuge (1646–48) of Lord Clarendon, who there began his History of the Rebellion, and of the fugitive Charles II in 1646 and 1649. Harbour works were begun in 1700, and the modern harbour dates from 1841. The marketplace (now Royal Square) was the scene of the French defeat at the Battle of Jersey (1781). The marketplace is dominated by the Court House, La Salle des Etats (States House), and the Public Library (founded 1736) and is overlooked (south) by Fort Regent (1806). Victoria College dates from 1852. About one-third of Jersey's population lives in St. Helier, which is the focus of island transport, commerce, government, and cultural activity. Pop. (2001) 28,310.