2Dissolved and divided between neighboring (sub-)provinces.
3Became the only sub-province left comprising Mountain Province in 1966, and therefore assumed the name of the mother province.
4Became the only sub-province left comprising Agusan in 1914, and therefore assumed the name of the mother province.
5Delimited to the downtown area of present-day Isabela City in 1973; dissolved in 1975.
6Legazpi City from 1948 to 1954 consisted of the present-day territories of Legazpi City and Daraga; this city was dissolved in 1954 into its two former constituent municipalities. Legazpi became a city on its own in 1959.