The Okhotsk-Manchurian taiga ecoregion is an area of coniferous forests in the Russian Far East, covering the Amur River delta, the west coast of the Okhotsk Sea, and the rugged extension of the northern Sikhote-Alin Mountains that run southwest-to-northeast through the Primorsky and Khabarovsk regions. It is the southernmost taiga forest in Eurasia. The ecoregion is distinguished from surrounding ecoregions by the slightly warmer climate due to the maritime influence and the shield of the mountains to the west, and by the mixing of flora and fauna species from Okhotsk-Kamchatka communities to the north and Manchurian species from the south. The forest at lower altitudes is "light taiga", and "dark taiga" at higher altitudes.

The Manchurian mixed forests ecoregion covers the forested hills surrounding the river plains of northern China, Russia, North Korea, and South Korea. The ecoregion supports a number of rare species due to the relative isolation, the diversity of habitat, with mixed forests of deciduous Mongolian oak and conifers of Korean pine. Because mountains rise above the region on three sides, with plains and wetlands below, the area supports high biodiversity as a transition zone.