My husband's great grandfather was Nicholas McGree b: 25 March 1827 Kilkenny County, Ireland. In 1860 he married Mary Collins b: 8 Sept 1836 in Kilkerrin, County Galway, Ireland. They came to the United States and settled in Marshan Township, near Hastings, Minnesota. They both died of the fever that swept the area in 1889.
Most McGree's/Magree's came from County Kilkenny in Ireland. They left Ireland and moved primarily to Australia and the United States. The research I have done shows that there were many Nicholas McGree's in Ireland at the same time as my husband's great grandfather.
I have a McGree/Magree surname data base if you are interested.