There are two prevailing versions as to how Sindangan got its name. First story has it that a native fisherman carrying a basketful of fish was asked by a Guardia Civil, "Que es el nombre de este lugar, Amigo?" The fisherman, who did not understand Spanish replied, "Indangan," thinking he was being asked as to the kind of fish that he caught. The Spaniard, on the other hand, heard it as "Sindangan" so he revealed the same to the other Spaniards. Since then, the place was called Sindangan. The second version has it that a group of Spaniards got attracted to some blooming plants in the fields so they asked a group of Visayan farmers nearby whether or not there were pests attacking the said plants. With a little knowledge of the language, the farmers replied "Sin" meaning no and "Dangan" meaning no pests. When combined, they form the word, "Sindangan" meaning a place with no pests. The municipality was once an isolated barangay of Katipunan not connected by road, the municipality of Sindangan began its corporate existence on December 23, 1936 by virtue of Executive No. 77 which was signed by the President of the Commonwealth of the Philippines, Manuel L. Quezon. Early settlers of the municipality belong to the Subanen tribe. Originally, they settled along the banks of Sindangan Bay. Just a mile across the river towards the north, an army camp was established which opened opportunities for many people. This resulted to the migration of farmers from Visayas and Luzon, and this also prompted the natives to move further into the hills and mountains leaving the lowlands to the more civilized farmers from the north. Since gaining corporate entity, administrators of the municipality initiated development which made Sindangan what it is today. This is attributed to the hard work and dedication of the 13 local chief executives who administered the affairs of Sindangan in close coordination with its constituents.
The 13 mayors of Sindangan are as follows: 1. Bartolome Lira, Sr. (appointed= 1936-1941) 2. Emilio Ortuoste (elected= 1941-1946) 3. Joaquin Macias (elected= 1946-1955) 4. Abundio Siasico (elected= 1955-1959) 5. Joaquin Macias (elected 1959-1963) 6. Filomena Macias (elected= 1963-1967) 7. Jose Tan (elected= 1967-1971) 8. Mariano S. Macias (elected= 1971-1979) 9. Ricardo S. Macias (elected= 1979-1986) 10. Engr. Crescente Y. Llorente, Jr. (appointed= 1986-1988) (elected= 1988-1981) (re-elected= 1991-1995) 11. Engr. Winnie O. Albos (elected/re-elected= 1995-2004) 12. Bert S. Macias (succession/elected= 2004-2010) 13. Nilo Florentino Z. Sy (elected= 2010-present)