Castilho (Portuguese pronunciation: [kasˈtiʎu]) is a municipality in the state of São Paulo, in Brazil.

It has an estimated population of 21,521 (as of 2021)[8] in an area of 1,065.318 km2 (411 sq mi),[7] and its elevation is of 378.46 m (1,242 ft) above the sea level.

[16] It contains part of the 8,885.33 hectares (21,956.1 acres) of the Mouth of the Aguapeí Private Natural Heritage Reserve, created in 2010.

[19] The company is currently an operator of cell phones, fixed lines, internet (fiber optics/4G) and television (satellite and cable).

It was a support structure for the operation of the Urubupungá complex, formed by the hydroelectric plants Ilha Solteira, Jupiá and Três Irmãos on Paraná river.