San Lorenzo (Spanish pronunciation: [san loˈɾenso], locally [ˌsaŋ loˈɾeŋso]; Spanish for "Saint Lawrence") is a town and municipality of Puerto Rico located in the eastern central region, north of Patillas and Yabucoa; south of Gurabo; east of Caguas and Cayey; and west of Juncos and Las Piedras.

[2] Hurricane Maria on September 20, 2017 triggered numerous landslides in San Lorenzo with the significant amount of rainfall.

[3][4] San Lorenzo is located in the eastern central region, north of Patillas and Yabucoa; south of Gurabo; east of Caguas and Cayey; and west of Juncos and Las Piedras.

The town is located on the San Lorenzo Batholith, which is a mountainous region composed of intrusive igneous rock.

The municipal buildings, central square and large Catholic church are located in a barrio referred to as "el pueblo".

[13] Between 2013 and until their arrest by the FBI in 2019, dozens of drug traffickers were operating in the Roosevelt neighborhood and near the Lorenzana public housing residential units in San Lorenzo.

The Fiestas Patronales Nuestra Senora de las Mercedes is a religious and cultural celebration that generally features parades, games, artisans, amusement rides, regional food, and live entertainment.