The first missionary to the island of Ireland arrived in Belfast in May 1840. He was followed on July 28 by Apostle John Taylor. More than 600 people heard Elder Taylor preach that evening in Newry.
Three days later, Thomas Tait was the first to be baptized. Two months later, Elder Theodore Curtis arrived in Ireland and established a branch (a small congregation) of 35 members in Hillsborough.
Read more about Latter-day Saints in Ireland.