 It was represented as part of the first district of Rizal from 1907 to 1972, and of Region IV from 1978 to 1984.It elected 2 assemblymen at-large to the Regular Batasang Pambansa from 1984 to 1986, and has been divided into two districts since the restoration of the House of Representatives in 1987.Of the country’s 238 legislative districts, the 1st Legislative District of Caloocan was the biggest in terms of population size, with 1.19 million persons.