Summerhill (Irish: Cnoc Críonáin) is a primarily residential area of Dublin, Ireland, on the Northside of the city located roughly between Talbot Street, Gardiner Street, Mountjoy Square, Amiens Street and Ballybough. It is in the Dublin 1 postal district. It is one of the most densely populated and economically deprived areas of the city. The area is known historically for containing a range of red brick Victorian and Georgian terraced avenues along streets such as Buckingham Street and Gardiner Street as well as for the Monto red-light district of Dublin and the Gloucester Diamond.