Huánuco is located in the central part of the country, it contains the three mountain ranges of the northern Andes of Peru and extends to the Ucayali River. The region is home to vast swaths of forests in the Amazon Basin. Its boundaries are:
- to the North: with the departments of La Libertad, San Martín, Loreto and Ucayali.
- to the South: with the Pasco department.
- to the East: with the Ucayali department.
to the West: with the Ancash and Lima departments
The region is divided into 11 provinces and 77 districts.
The departmental territorial surface of 36,848.85 Km², represents 2.87% of the national territory, in which seven of the eight Natural Regions can be found (except for the Chala region). If we refer to the three natural regions: covered in 64.06% of mountains, 23.84% of hills, 2.77% of piedmont and 8.33% of plains. The territory of the department has been widely dissected (sunken, deepened) by orogenic processes closely related to the Andean uprising, so Huánuco contains in its interior the three mountain ranges of the northern Andes of Peru; the western, the central and the oriental. These chains have originated as much by the Andean uprising as by the carving that in millions of years have made the Marañón, Huallaga and Pachitea rivers, rivers that run almost parallel from south to north and that help to shape the Huanuco territory, generating three large spatial assemblies: the Marañón basin, the Huallaga basin and the Pachitea basin.