According to the census, it has a population of , people. Due to its location just south of Manila , Pasay quickly became an urban town during the American colonial period. In local folk history about the period before the arrival of Spanish colonizers, Pasay is said to have been part of Namayan sometimes also called Sapa , a confederation of barangays which supposedly controlled territory stretching from Manila Bay to Laguna de Bay , and which, upon the arrival of the Spanish, eventually became known as Santa Ana de Sapa modern day Santa Ana, Manila.
Of the many religious orders that came, it was the Augustinian Order who would figure predominantly in the evangelisation of Pasay.
Having control over Pasay, they converted the area into an extensive agricultural estate known as the Hacienda de Meysapan. The promise of space in Heaven prompted early native converts to donate their possessions to the Church, with folklore recounting how a baptized Pasay on her deathbed donated her vast estate to the Augustinians. Most of Pasay went to friar's hands either via donation or by purchase; many natives were also forced to divest of their properties to cope with stringent colonial impositions.
In , notable residents of Pasay submitted a petition to handle their political and religious matters independently, proposing to rename the town "Pineda" , in honor of Don Cornelio Pineda, a Spanish horticulturist who was their benefactor. Pasay produced numerous heroes during the Philippine Revolution.
Several women also fought for the cause of the Katipunan including Marcela Marcelo. General Emilio Aguinaldo meanwhile declared the independence of the First Philippine Republic on June 12, , and issued decrees providing political reorganization in the country.
