Legislative districts of Laguna

Laguna was initially divided into two representative districts in 1907.

When seats for the upper house of the Philippine Legislature were elected from territory-based districts between 1916 and 1935, the province formed part of the fourth senatorial district which elected two out of the 24-member senate.

By virtue of Executive Orders No. 84 and 103 issued by Philippine Executive Commission Chairman Jorge Vargas in 1942, the municipality of Infanta (including what is now General Nakar and Real) and the Polillo Islands were transferred to Laguna's jurisdiction, a setup which only lasted for the duration of the Second World War. Two delegates represented the expanded province in the National Assembly of the Japanese-sponsored Second Philippine Republic: one was the provincial governor (an ex officio member), while the other was elected through a provincial assembly of KALIBAPI members during the Japanese occupation of the Philippines. San Pablo, being a chartered city, was represented separately in this short-lived legislative body. Upon the restoration of the Philippine Commonwealth in 1945, the province retained its two pre-war representative districts.

The province was represented in the Interim Batasang Pambansa as part of Region IV-A from 1978 to 1984, and elected four representatives, at large, to the Regular Batasang Pambansa in 1984. Laguna was reapportioned into four congressional districts under the new Constitution[1] which was proclaimed on February 11, 1987, and elected members to the restored House of Representatives starting that same year.

The passage of Republic Act No. 10658[2] on March 27, 2015 separated from the first district the city of Biñan, which first elected its separate representative beginning in the 2016 elections. However, for the purposes of electing Sangguniang Panlalawigan members, Biñan remains part of the province's 1st Sangguniang Panlalawigan District.[3]

The passage of Republic Act No. 11078[4] on July 23, 2018 separated from the second district the city of Calamba, which elected its separate representative beginning in the 2019 elections. However, for the purposes of electing Sangguniang Panlalawigan members, Calamba remains part of the province's 2nd Sangguniang Panlalawigan District.[5]

The passage of Republic Act No. 11395[6] on August 28, 2019 will have the effect of separating from the first district the city of Santa Rosa, which will elect its separate representative beginning in the 2022 elections. However, for the purposes of electing Sangguniang Panlalawigan members, Santa Rosa will remain part of the province's 1st Sangguniang Panlalawigan District.

• Cities: San Pedro, Santa Rosa
• Population (2015): 679,576

• City: Cabuyao
• Municipalities: Bay, Los Baños
• Population (2015): 482,896

• City: San Pablo
• Municipalities: Alaminos, Calauan, Liliw, Nagcarlan, Rizal, Victoria
• Population (2015): 550,593

• Municipalities: Cavinti, Famy, Kalayaan, Luisiana, Lumban, Mabitac, Magdalena, Majayjay, Paete, Pagsanjan, Pakil, Pangil, Pila, Santa Cruz, Santa Maria, Siniloan
• Population (2015): 534,502

• Legislative district of San Pablo
• Legislative district of Biñan
• Legislative district of Calamba
• Legislative district of Santa Rosa