| State: | PR |
| Type: | PR |
| Route: | 820 |
| Alternate Name: | Spanish; Castilian: Carretera Marzán |
| Length Km: | 2.1 |
| Established: | 1953 |
| Direction A: | West |
| Terminus A: | in Maricao |
| Direction B: | East |
| Terminus B: | in Río Lajas |
| Municipalities: | Vega Alta, Toa Alta |
| Previous Type: | Ter |
| Previous Route: | 819 |
| Next Type: | Ter |
| Next Route: | 821 |
Puerto Rico Highway 820 (PR-820) is an east–west road between the municipalities of Toa Alta and Vega Alta in Puerto Rico. With a length of 2.1km (01.3miles), it extends from PR-823 in Río Lajas barrio to its intersection with PR-677 and PR-678 in Maricao barrio.
Puerto Rico Highway 820 is a rural road with a single lane per direction along its entire length. In Toa Alta, PR-820 leaves from PR-823, passing through Marzán neighborhood until the Vega Alta municipal limit. In Vega Alta, PR-820 has a short length from the Toa Alta municipal limit until its western terminus at PR-677 and PR-678 intersection. The entire length in Toa Alta is located in Río Lajas barrio, while in Vega Alta it is located entirely in Maricao barrio.