Hatillo (Spanish pronunciation: [aˈtiʎo]) is a municipality located in Puerto Rico's north coast, bordered by the Atlantic Ocean to the north, Lares and Utuado to the south, Camuy to the west, and Arecibo to the east. According to the 2000 US Census Hatillo is spread over nine barrios and Hatillo Pueblo (the downtown area and the administrative center of the city). It is part of the San Juan-Caguas-Guaynabo Metropolitan Statistical Area.
Agustín Ruiz Miranda, a Canarian immigrant, founded Hatillo on approximately ten cuerdas (a cuerda is 0.97 acre, also called a Spanish acre) in 1823. Miranda granted this land on the condition that public buildings be erected and wide streets be built, and that the remaining land be sold or used for homes.
In its first year, Hatillo had 910 people; increasing to 2,663 inhabitants the following year distributed among the central town and the barrios of Carrizales, Capáez, Naranjito, Corcovado, Buena Vista, (formerly Yeguada Occidental), Campo Alegre, (formerly Yeguada Oriental), Pajuil, Bayaney, Aibonito, and Barrio Pueblo. Barrio Pajuil had disappeared by the 1940 census being divided up between Buena Vista, Naranjito, Corcovado and Campo Alegre barrios. There were also two sugarcane plantations named “Hacienda Santa Rosa” measuring 150 cuerdas and “Hacienda Perseverancia” at 50 cuerdas.
Puerto Rico was ceded by Spain in the aftermath of the Spanish–American War under the terms of the Treaty of Paris of 1898 and became a territory of the United States. In 1899, the United States conducted its first census of Puerto Rico finding that the population of Hatillo was 1,148.
Hatillo, like several other municipalities on the island, experienced boundary changes from the 1902 municipality consolidation law (Consolidación de Ciertos Términos Municipales de Puerto Rico) in which Hatillo was annexed temporarily into neighboring Camuy. Three years later the territorial legislature approved the reformation of Hatillo as a separate municipality (independent town) from Camuy in 1905.