seaport and county seat, County Wicklow, Ireland, south-southeast of Dublin. St. Mantan built a church there in the 5th century; and the town later became a settlement of the Vikings, who renamed it Wykingalo (Vikings' Lough). After the Anglo-Norman invasion in the 12th century, it was granted to Maurice Fitzgerald, who built Black Castle. From then until the 17th century the town suffered many attacks. There are remains of a 13th-century Franciscan friary and an ancient fort. The town is now a coastal holiday resort with some light industry. Pop. (2002) 7,031.

county in the province of Leinster, Ireland. It is bounded by the counties of Wexford (south), Carlow and Kildare (west), and Dublin (north) and by the Irish Sea (east). County Wicklow includes much of the Leinster Chain mountain range, notably the Wicklow Mountains, and has fertile lowland areas. Much of its coast comprises rocky cliffs and excellent sand beaches. The main summits of the Leinster Chain are above 2,000 feet (600 metres), with Lugnaquillia Mountain the highest at 3,039 feet (926 metres); in places it is marked by waterfalls and river gorges. South of Lugnaquillia the range is not a significant barrier, but the Wicklow Mountains are nowhere crossed at an elevation of less than 1,000 feet (300 metres); the Military Road through the mountains, built after a rebellion in 1798, runs at an elevation of more than 1,000 feet for more than 20 miles (30 km).

Tourism is among the county's leading industries. Dairying and livestock production (particularly sheep) are also important. Major crops include barley, oats, potatoes, and wheat. Historically, there was granite and slate quarrying, and there are deposits of lead, copper ore, and pyrites, though much production has ceased. At Pollaphuca on the River Liffey there is a large hydroelectric plant. The Avoca woolen mill, dating from 1723, is Ireland's oldest still in operation. In the last part of the 20th century industry diversified, and the county now produces various products, including computer equipment and pharmaceuticals.

Population in the county began to grow after the railway was built in 1851, particularly in Bray, which is a seaside resort and residence for Dublin commuters and an industrial centre. Greystones and Delgany are also resorts and residential centres. Wicklow is a coastal market town with some industry. Arklow still has some shipping, a pottery, and a strong market trade. A county council meets in Wicklow town, and there is a county manager. Arklow, Bray, and Wicklow are urban districts.

Wicklow's name is derived from the Norse vykinglo (“meadow”), and there were Viking settlements in the area about the 8th century. Although Wicklow town was a Norse harbour, the countryside remained in native hands. With its rugged landscape, Wicklow was long known as a place for fugitives and for those who sought to prey on the inhabitants of the Dublin area. MacMurroughs, O'Byrnes, O'Tooles, and others constantly raided the lower lands of the English Pale (territory) until 1601. The citizens of Wicklow played a prominent role in the Wexford uprising of 1798, harbouring many of the rebels. Among Wicklow's famous natives is Charles Stewart Parnell (Parnell, Charles Stewart), a leader in the struggle for Home Rule in the late 18th century. Area 783 square miles (2,027 square km). Pop. (2002) 114,676; (2006) 126,194.