The Allegheny Highlands forests are a temperate broadleaf and mixed forests ecoregion located in a large part of the Allegheny Plateau physiographic province, including both unglaciated and glaciated portions, in Pennsylvania and New York within North America, as defined by the World Wildlife Fund. The United States EPA defines the area as belonging to the Northern Central Appalachians and Northern Appalachian Plateau and Uplands ecoregions.

Temperate broadleaf and mixed forest is a temperate climate terrestrial habitat type defined by the World Wide Fund for Nature, with broadleaf tree ecoregions, and with conifer and broadleaf tree mixed coniferous forest ecoregions.