Emilio Ramon Pelayo Ejercito III, commonly known as E. R. Ejercito, is a Filipino actor and former governor of Laguna from 2010 until his removal in 2014. Prior to his election as governor, he served as mayor of Pagsanjan, Laguna, from 2001 until 2010. He is the son of actor George Estregan and the nephew of former President and former Manila Mayor Joseph Estrada.

Pagsanjan, officially the Municipality of Pagsanjan, is a 3rd class municipality in the province of Laguna, Philippines. According to the 2020 census, it has a population of 44,327 people.