[3] With a length of 4.3 km (2.7 mi), it begins at its intersection with PR-149 in Hato Viejo barrio and ends at its junction with PR-155 in Barahona.

[4] Due to its rural characteristics, PR-633 consists of one lane per direction for its entire length.

In Ciales, it extends from PR-149 intersection to the Morovis municipal limit, making its way through Hato Viejo barrio.

[5] In Morovis, PR-633 extends to the east within Barahona barrio from the Ciales municipal limit until its eastern terminus at PR-155 junction.

20, a highway that led from Naranjito to Ciales through Corozal and Morovis until the 1953 Puerto Rico highway renumbering, a process implemented by the Puerto Rico Department of Transportation and Public Works (Spanish: Departamento de Transportación y Obras Públicas) that increased the insular highway network to connect existing routes with different locations around Puerto Rico.