The Holarctic is the terrestrial ecozone that encompasses the majority of habitats found throughout the northern continents of the world. This region is divided into the Palearctic, consisting of North Africa and all of Eurasia (with the exception of the southern Arabian Peninsula, Southeast Asia, and the Indian subcontinent), and the Nearctic, consisting of North America north of Southern Mexico. These are further subdivided into a variety of ecoregions. Many ecosystems, and the animal and plant communities that depend on them, are found across multiple continents in large portions of this ecozone. The continuity of these ecosystems results from the shared glacial history of the ecozone. The floristic Boreal Kingdom corresponds to the Holarctic ecozone.

The Holarctic is the terrestrial ecozone that encompasses the majority of habitats found throughout the northern continents of the world. This region is divided into the Palearctic, consisting of North Africa and all of Eurasia (with the exception of the southern Arabian Peninsula, Southeast Asia, and the Indian subcontinent), and the Nearctic, consisting of North America north of Southern Mexico. These are further subdivided into a variety of ecoregions. Many ecosystems, and the animal and plant communities that depend on them, are found across multiple continents in large portions of this ecozone. The continuity of these ecosystems results from the shared glacial history of the ecozone. The floristic Boreal Kingdom corresponds to the Holarctic ecozone.