It is a 4th class municipality in the province of Rizal, Philippines.
According to the latest census, it has a population of 28,738 people in 4,759 households.
The genesis of the name Jalajala started from a legend. Punta, one of the present barangay was the seat of the early settlement later to be called "Halaan". During the summer months of April and May the shores of Punta along the Laguna de Bay was covered with a variety of shells locally known as Halaan. The natives, when asked by Spanish visitors "Como se llama este sitio?" replied "Halaan po" thinking that they were asking for the shell. The Spaniards on the other hand thinking it is the name of the place, began calling it "Halaan" which was later changed to Jalajala.