The departments (Spanish: departamentos), informally called regions (Spanish: regiones), are the first-level administrative subdivisions of Peru. According to the Organic Law of Regional Governments, each department is administered by a regional government and a legislature responsible for administration, economic planning, and public services. These governments operate with autonomy while still coordinating with national authorities. Each department is led by a regional governor, who is elected by popular vote for a four-year term, and is responsible for implementing regional policies, managing budgets, and overseeing infrastructure projects. The governor is supported by a regional legislative council, composed of elected representatives from different provinces within the department. This council approves budgets, monitors public investments, and ensures government accountability.

There are 24 departments in total, as well as two provinces that operate under a special regime: Callao and Lima. The former does not belong to any department since 1836, but is nevertheless administered by a regional government of its own. The latter is administered by the Metropolitan Municipality of Lima, which is equal in status to a regional government.

Each department is further divided into provinces, which are governed by provincial municipalities. These municipalities are led by a mayor and a council, also elected by the population. They manage local services such as urban planning, transportation, and sanitation. Within the provinces, there are district municipalities, responsible for more localized governance, including community development, minor public works, and social programs. This three-tiered structure—regional, provincial, and district—ensures that governance reaches all levels, from large cities to rural villages.

Although the departments have autonomy, they still follow national laws and policies set by the central government. The National Decentralized Secretariat (Spanish: Secretaría de Descentralización), under the Presidency of the Council of Ministers, oversees regional governments to ensure efficiency and compliance. Departments also coordinate with national ministries for education, health, transportation, and security, receiving funding and technical support. This structure allows departments to manage their own affairs while maintaining a connection to the broader national development strategy.

After declaring its independence in 1821, Peru was divided into departments (Spanish: departamentos), which grew in number from four in 1821 to eleven in 1822 and to twenty-four in 1980:

As political and economic power increasingly concentrated in Lima, the capital city, several administrations attempted to decentralize the country with little success. The 1979 Peruvian Constitution contained provisions for the decentralization of power through the creation of autonomous regions, but they were not implemented.

During the later years of the 1985–1990 presidency of Alan García, the government faced the prospect of losing the 1990 presidential elections because of a widespread economic crisis and faltering public support. As a way of creating an alternative source of power, the regime established twelve autonomous regions on January 20, 1989, in the hope of winning some elections at this level. However, due to the haste of their creation, these regional governments were not provided with fiscal resources of their own, so they depended on the goodwill of the central government for funding. Formation of another region was delayed by the reluctance of the Constitutional Province of Callao to merge with the Lima Department. Originally San Martín and La Libertad Regions formed the sole region of San Martín-La Libertad but later were split.

The 1990 presidential elections were marked by the discrediting of political parties as evidenced in the election of Alberto Fujimori, an independent candidate. Fujimori withheld financial transfers to regional governments and then, on December 29, 1992, replaced them with government-designated Transitory Councils of Regional Administration (Spanish: Consejos Transitorios de Administración Regional). Having dissolved Congress in the 1992 Peruvian constitutional crisis, Fujimori called an election for a Constitutional Assembly which drafted the 1993 Constitution. This new text included provisions for the creation of regions with autonomous, elected governments, but they were not carried out. A framework law on decentralization (Spanish: Ley Marco de Descentralización) issued on January 30, 1998, confirmed the permanence of transitory councils, now under the supervision of the Ministry of the Presidency.