[2] With a length of 1.8 km (1.1 mi), this road can be seen as the Alt 159, since it was the original alignment of PR-159 through the municipal center.

[3] This highway consists of one lane in each direction for most of its length.

[5] After those intersections, PR-891 heads to the east, leaving the downtown area until its end at PR-159 in eastern Barrio Pueblo.

10, a highway that led from Dorado to Coamo through Toa Alta, Corozal and Orocovis 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.

[10] Its original way currently corresponds to PR-165, from PR-8865 in Dorado to PR-159 in Toa Alta;[11] PR-159, from PR-165 in Toa Alta to PR-568 in Corozal, except in downtown area, where PR-891 replaces PR-159;[3] PR-568, from PR-159 in Corozal to PR-5155 in Orocovis;[12] PR-5155, from PR-568 north of downtown to PR-155 south of downtown, and PR-155, from PR-5155 in Orocovis to PR-14 in Coamo.