Irish immigrants arrived in Lawrence at its birth, which coincided with the Great Famine of the mid-1840s, the event that drove great numbers of Irish out of Ireland. The Great Stone Dam, constructed in from 1845–1848 to power the textile mills, was largely built by Irish laborers. The first Irish immigrants settled in the area south of the Merrimack River near the intersection of Kingston Street and South Broadway (In December 1848, the Reverend James O'Donnell erected "old" St. Mary's Church.In 1869,[27 the Irish were able to collect sufficient funds to form their own church, St. Patrick's, on South Broadway. Although immigration slowed down, The Irish community in Lawrence is still large.