Coordinates: 50°26′23″N 2°12′38″E / 50.4397°N 2.2106°E / 50.4397; 2.2106

Érin is a commune in the Pas-de-Calais department in the Nord-Pas-de-Calais region in France.

Érin is a small village on the south side of the small river, the Ternoise which flows through St.Pol-sur-Ternoise and joins the River Canche at Hesdin. The geology of the area is like that of the Somme River valley to its south. The Ternoise valley is the most northerly flowing in the syncline to the south of the Variscan front. The London-Brabant Massif underlies the land to the north.

The road, D94 follows the river between St.Pol and Hesdin. Alongside it runs the Arras to Boulogne-sur-Mer railway.

During the First World War, the principal depôt of the British Army unit, then known as the Tank Corps, developed at Érin. The Tank Corps developed through the Heavy branch of the Machine Gun Corps from the Heavy Section. This was founded in March 1916. The depôt was known as the Central Workshops and was set up in January 1917 under the command of Major Brockbank. Other parts of the organization were nearer the neighbouring villages of Bermicourt (maintenance school) and Fleury (wireless and signals).

Mary O'Hara (born in Sligo on 12th May 1935) is an Irish soprano and harpist from County Sligo. O'Hara achieved fame on both sides of the Atlantic in the late 1950s and early 1960s. Her recordings of that period influenced a generation of Irish female singers who credit O'Hara with influencing their style, among them Carmel Quinn, Mary Black, and Moya Brennan, among others. In his autobiography Memoirs of an Irish Troubadour (2002) Liam Clancy wrote how O'Hara's music inspired and influenced him and others of the Folk Revival period.

Mary won her first competitions, Sligo's annual Music and Drama singing competition, at the age of eight and made before she left school at the age of 16. She went on to perform at Edinburgh International Fringe Festival with the Dublin University Players, BBC's Quite Contrary and The Ed Sullivan Show, before she starred in her own BBC television series. Her first recording contract was with Decca Records. Part of her extensive music career included Mary spending a considerable amount of time on the Aran Islands collecting folk music and acquiring fluent Gaelic.