The ecoregion covers 13,300 square kilometres (5,100 sq mi), extending from just north of the California-Oregon border south, to southern Monterey County.

The greatest concentration of remaining Old-growth forest are in the northernmost portion of the ecoregion, primarily within Humboldt and Del Norte counties.

Major urban centers located within this ecoregion include the montane portions of various cities of the San Francisco Peninsula, Fort Bragg, Eureka, and Brookings.

These are the tallest forests on Earth, with individual redwood (Sequoia sempervirens) trees reaching heights of 100 metres (330 ft).

Other hardwoods include California bay laurel (Umbellularia californica), red alder (Alnus rubra), madrone (Arbutus menziesii), and bigleaf maple (Acer macrophyllum).

The shrub understory is dense and diverse; beaked hazel (Corylus cornuta), evergreen huckleberry (Vaccinium ovatum), Pacific rhododendron (Rhododendron macrophyllum), salal (Gaultheria shallon), Sadler's oak (Quercus sadleriana), dwarf Oregon-grape (Mahonia nervosa), and poison oak (Toxicodendron diversilobum) are typically found.

), California brome (Bromus carinatus), Nootka reedgrass (Calamagrostis nutkaensis), California oatgrass (Danthonia californica), red fescue (Festuca rubra), Idaho fescue (Festuca idahoensis), tufted hair-grass (Deschampsia caespitosa), prairie Junegrass (Koeleria macrantha), tall trisetuem (Trisetum canescens).

[7] Northern coastal scrub consists of shrublands found at elevations below 1,500 feet (460 m) on bluffs, terraces, dunes, and hills near the coast.

Characteristic species include coyote brush (Baccharis pilularis), yellow bush lupine (Lupinus arboreus), blueblossom (Ceanothus thyrsiflorus), seaside woolly sunflower (Eriophyllum stoechadifolium), sticky monkey-flower (Mimulus aurantiacus), poison oak (Toxicodendron diversilobum), California blackberry (Rubus ursinus), thimbleberry (Rubus parviflorus), salmonberry (Rubus spectabilis), coffeeberry (Rhamnus californica), oceanspray (Holodiscus discolor), salal (Gaultheria shallon), cow parsnip (Heracleum maximum), and western sword fern (Polystichum munitum).

menziesii), California sycamore (Platanus racemosa), coast live oak (Quercus agrifolia), and bigleaf maple (Acer macrophyllum).

In forests, California blackberry (Rubus ursinus), creeping snowberry (Symphoricarpos mollis), toyon (Heteromeles arbutifolia), and poison oak (Toxicodendron diversilobum) are common in the understory.