Immediately north and northwest of Port of Spain lie the suburbs of Cascade, St. Ann's, Maraval and Diego Martin. The last two districts fall outside the municipal boundary, but are sometimes considered extensions of the city. St. Ann's is notable for being the location of the Prime Minister's official residence and diplomatic centre. Cascade, a mainly suburban area with treed lot type housing is located to the south-eastern area of St. Ann's. Cascade borders St. Ann's by a hill named Mount Hololo, a neighbourhood of both middle class and exclusive housing developments.