Calauan is a second class municipality in the province of Laguna, Philippines. According to the 2010 census, it has a population of 74,890 people. The town got its name from the term kalawang, which means rust. Folklore has it that the town got its name when the Spanish started construction of the Municipal Church and water seeped in from the holes dug into the ground for the Church's foundation. The water was colored brown and rusty in character hence the name Calauan (Kalawang).