The North Circular Road (Irish: An Cuarbhóthar Thuaidh) - designated as R101 regional road - is an important thoroughfare on the northside of Dublin, in Ireland. The regional road was long considered the northern boundary of the city and still separates the city centre from the inner suburbs. It runs from the Phoenix Park in the west through Phibsboro, to North Wall in the east and is the location of a number of important institutions, The Mater Hospital, Dalymount Park and Mountjoy Prison are on the North Circular Road and both Croke Park and St.