With a length of 2.5 kilometers (1.6 mi), it begins at its intersection with PR-2 in Candelaria barrio and ends at its junction with PR-862 on the Toa Baja–Toa Alta–Bayamón municipal tripoint.

[2] This highway has a single lane per direction in the entire length and provides access to several communities and neighborhood developments between Candelaria, Mucarabones and Hato Tejas barrios.

[3] Located within Candelaria barrio, PR-863 extends to the south from PR-2 junction to PR-819 intersection.

Then, it turns to the southeast through southeastern Candelaria until its terminus at PR-862 junction on the Toa Baja's southernmost point.

[5] The current numerical designation corresponds to 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.