- * All sub-provinces were temporarily abolished during the Japanese occupation of the Philippines (1942–1945).
- 1 Converted to full-fledged province.
- 2 Dissolved and divided between neighboring (sub-)provinces.
- 3 Became the only sub-province left comprising Mountain Province in 1966, and therefore assumed the name of the mother province.
- 4 Became the only sub-province left comprising Agusan in 1914, and therefore assumed the name of the mother province.
- 5 Delimited to the downtown area of present-day Isabela City in 1973; dissolved in 1975.
- 6 Legazpi 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.
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