The Municipio of Mariel is one of the fifteen municipios in the province of Pinar del Río, Cuba. This municipio covers a surface of 172 square kilometers.

Note: A "municipio" (plural: municipios) is the first political division of the provinces in Cuba. It is similar, in many ways, to the county or parish in which a state is divided in the United States.

This municipio is located to the extreme northeast of the province. To the east it borders with the Municipio of Caimito de Guayabal in Havana province; to the south with the Municipio of Guanajay; and to the west with the Municipio of Cabañas. The Gulf of Mexico washes Mariel's northern coast.

Population: The population of this municipio in 1953 was 13,667 persons.

Jurisdiction: City Hall was created the 1st of July of 1866. In 1940 the Municipio of Mariel was part of the judicial party and the fiscal district of Guanajay.

Barrios: The "barrios" (singular: barrio) are similar to the electoral districts in which a county is divided in the United Sates.

The barrios of Mariel in 1943 were: Boca, Guajaibón, Macagual, Pueblo, Quiebra Hacha and San Juan Bautista.

Boca: In 1943 it had a population of 1,510 persons.

Guajaibón: It is located six kilometers from the city of Mariel.

Macagual: It is located three kilometers from the city of Mariel.

Pueblo: The city of Mariel, the municipio's seat of government.

Quiebra Hacha: It is located seven kilometers from the city of Mariel. The town of Quiebra Hacha is in this barrio.

San Juan Bautista: It is located seven kilometers from the city of Mariel.