Sonora is a state in Northwestern Mexico that is divided into 72 municipalities. According to the 2020 Mexican census, it is the eighteenth most populated state with 2,944,840 inhabitants and the 2nd largest by land area spanning 179,354.7 square kilometres (69,249.2 sq mi).[1][2] The largest municipality by population is Hermosillo, with 936,263 residents (31.79% of the state's total), while the smallest is Onavas with 365 residents.[1] The largest municipality by land area is also Hermosillo which spans 15,724.30 km2 (6,071.19 sq mi), and the smallest is San Felipe de Jesús with 151.30 km2 (58.42 sq mi).[2] The newest municipalities are Benito Juárez and San Ignacio Río Muerto, established in 1996.[3]
Municipalities in Sonora are administratively autonomous of the state according to the 115th article of the 1917 Constitution of Mexico.[4] Every three years, citizens elect a municipal president (Spanish: presidente municipal) by a plurality voting system who heads a concurrently elected municipal council (ayuntamiento) responsible for providing all the public services for their constituents. The municipal council consists of a variable number of trustees and councillors (regidores y síndicos).[5] Municipalities are responsible for public services (such as water and sewerage), street lighting, public safety, traffic, and the maintenance of public parks, gardens and cemeteries.[6] They may also assist the state and federal governments in education, emergency fire and medical services, environmental protection and maintenance of monuments and historical landmarks. Since 1984, they have had the power to collect property taxes and user fees, although more funds are obtained from the state and federal governments than from their own income.[6]