San Juan is a small congested City located in the heart of Metro Manila. It is among the smallest political subdivisions of the Metropolis. Its land area of 5.94 sq. kms. accounts for less than 1 percent of the region. Located in the very center of the Metropolis, it is bounded by Manila in the west, Quezon City in the north and Mandaluyong in the east and south, at coordinates 12º 36’ latitude due north and 121º 02 longitude due east.
San Juan may be described as a congested town with very little space for expansion. It is predominantly residential with scattered commercial and manufacturing establishments. The City is politically divided into 2 Districts with 10 barangays in District 1 and 11 barangays in District 2.
Because of its central location and its accessibility to and from all points of the region, San Juan has attracted migrants from other areas. The presence of informal settlements is a problem the city government has to perennially contend with.