Yabucoa (Spanish pronunciation: [ʝaβuˈkoa]) is a municipality in Puerto Rico located in the eastern region, north of Maunabo; south of San Lorenzo, Las Piedras and Humacao; and east of Patillas. Yabucoa is spread over 9 wards and Yabucoa Pueblo (the downtown area and the administrative center of the city). It is part of the San Juan-Caguas-Guaynabo Metropolitan Statistical Area.
The region of what is now Yabucoa belonged to the Taíno region of Guayaney, which covered a portion of the southeast region of Puerto Rico. The region was led by cacique Güaraca. After the Spanish colonization, the region of Yabucoa belonged to Humacao, and its territory was mostly used for cattle and farming. Yabucoa, as a town, was founded in October 3, 1793 when Don Manuel Colón de Bonilla and his wife, Doña Catalina Morales Pacheco, donated the lands to the people.
The municipality of Yabucoa is located in the south-eastern coast of Puerto Rico. The valley of Yabucoa is surrounded by the hills of the San Lorenzo Batholith on three sides and by the Caribbean Sea on the fourth. The hills surrounding the Yabucoa valley as well as the bedrock underlying the alluvium in the valley are composed of the San Lorenzo Batholith, a large, igneous intrusive body emplaced during the Late Cretaceous (Rogers, 1977; Rogers and others, 1979). The San Lorenzo Batholith is a composite body that is composed of gabbro (Kd), diorite, tonalite, granodiorite, and quartz monzonite.