Slemish, historically called Slieve Mish, is a hill in County Antrim, Northern Ireland. It lies a few miles east of Ballymena, in the townland of Carnstroan. Tradition holds that Saint Patrick, enslaved as a youth, was brought to this area and tended sheep herds on Slemish, and that during this time he found God. Slemish is the remains of the plug of an extinct volcano. The plug is made of olivine dolerite and was formed during the Palaeogene period of the Earth's geological history.