Piracaia is a municipality located in the state of São Paulo, Brazil. It covers a total land area of 385.64 square kilometers (148.90 square miles) and maintains a population density of approximately 67.51 inhabitants per square kilometer.
The municipality was originally established in 1859 under the name Santo Antônio da Cachoeira. It was officially renamed Piracaia on August 20, 1906. According to the 2022 Brazilian census, the population was recorded at 26,029, with an estimated population of 26,795 in 2025.