Puerto Rico Highway 504 (PR-504) is a tertiary[2] state[3] highway in the municipality of Ponce in Puerto Rico. With a length of 6.9 km (4.3 mi), the road runs south to north, and mostly along the Río Chiquito in barrio Portugués Rural. Its southern terminus is at an intersection with PR-503, near PR-10 at the southern edge of Barrio Portugués, and the northern terminus is located at PR-505 on the Machuelo Arriba–Portugués–Montes Llanos tripoint.
The road is a mountainous two-way one-lane road and thus very difficult to navigate when traffic is coming from the opposite direction. In addition most of the road has numerous steep sharp curves and should be driven only with vehicles in top mechanical condition, preferably all-wheel drive sedans, as drivers of SUVs reportedly feel less in control of their vehicles. The road should not be driven after nightfall.
The road is 6.9 km (4.3 mi) kilometers long. At kilometer mark 3.0 km (1.9 mi), PR-504 connects with PR-588 (also known as Camino Pandora or Camino Río Chiquito) heading west towards Sector El Hoyo. PR-588's northern terminus is at kilometer 7.2 km (4.5 mi) of PR-505 in Barrio Montes Llanos.
The entire route is located in Ponce.