The Willapa Hills is a geologic

Geology

Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

, physiographic, and geographic

Geography

Geography is the science that studies the lands, features, inhabitants, and phenomena of Earth. A literal translation would be "to describe or write about the Earth". The first person to use the word "geography" was Eratosthenes...

 region in southwest Washington. When described as a physiographical province, the Willapa Hills are bounded by the Pacific Ocean

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 to the west, the Columbia River

Columbia River

The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...

 to the south, the Olympic Mountains

Olympic Mountains

The Olympic Mountains is a mountain range on the Olympic Peninsula of western Washington in the United States. The mountains, part of the Pacific Coast Ranges, are not especially high - Mount Olympus is the highest at - but the western slopes of the Olympics rise directly out of the Pacific...

 to the north, and the Cascade Range

Cascade Range

The Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...

 to the east. Some definitions place the Puget Lowland physiographic province east of the Willapa Hills. Included within the province are the Black Hills

Black Hills (Washington)

The Black Hills are a small range of hills in Thurston and Grays Harbor counties of Washington. They are a subset of the Willapa Hills. Capitol Peak is the highest peak in the range....

, the Doty Hills, and a number of broad river valleys, some of which open up into broad estuaries

Estuary

An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

 on the Pacific such as Grays Harbor and Willapa Bay

Willapa Bay

Willapa Bay is a bay located on the southwest Pacific coast of Washington state in the United States. The Long Beach Peninsula separates Willapa Bay from the greater expanse of the Pacific Ocean. With over of water surface Willapa Bay is the second largest estuary on the United States Pacific coast...

. Other definitions do not include the Black Hills. The USGS GNIS defines the Willapa Hills as bounded by the Columbia River to the south and the Chehalis River to the north, without giving specific east and west bounds. The Willapa Hills are one of the Pacific Coast Ranges

Pacific Coast Ranges

The Pacific Coast Ranges and the Pacific Mountain System are the series of mountain ranges that stretch along the West Coast of North America from Alaska south to Northern and Central Mexico...

, which continue north as the Olympic Mountains and south, across the Columbia River, as the Oregon Coast Range

Oregon Coast Range

The Oregon Coast Range, often called simply the Coast Range and sometimes the Pacific Coast Range, is a mountain range, in the Pacific Coast Ranges physiographic region, in the U.S. state of Oregon along the Pacific Ocean...

.

The highest point is 3087 feet (940.9 m) Boistfort Peak

Boistfort Peak

Boistfort Peak, also called Baw Faw Peak is a peak in the Willapa Hills in Washington state. The summit was once the site of a fire lookout....

. The Willapa Hills are the lowest uplands in the entire Pacific Coast Range system. Almost all of the land is privately held and has been repeatedly logged. Only a few long corners remain with virgin forest. Alders less than twenty years old are typically harvested for pulp mill

Pulp mill

A pulp mill is a manufacturing facility that converts wood chips or other plant fibre source into a thick fibre board which can be shipped to a paper mill for further processing. Pulp can be manufactured using mechanical, semi-chemical or fully chemical methods...

s.

The Willapa Hills receive abundant rainfall and a number of rivers originate in the region, including the Chehalis River, Willapa River

Willapa River

The Willapa River is a river on the Pacific coast of southwestern Washington in the United States, approximately long. It drains an area of low hills and a coastal plain into Willapa Bay, a large estuary north of the mouth of the Columbia River....

, North River

North River (Washington)

The North River is a river, approximately long, in western Washington, in the United States. It empties into Willapa Bay, the first large estuary on the Washington coast north of the Columbia River....

, Bone River

Bone River

The Bone River is a short river in the U.S. state of Washington. It is about long.-Course:The Bone River originates in the hills of the southwestern part of Washington, close to the source of the North Fork Palix River. It flows generally west, emptying into Willapa Bay near Bay Center just north...

, Niawiakum River

Niawiakum River

The Niawiakum River is a short river in the U.S. state of Washington. It is approximately long.-Course:The Niawiakum River originates in the hills of the southwestern part of Washington. It flows generally west, emptying into Willapa Bay near Bay Center and the mouth of the Palix River. The...

, Palix River

Palix River

The Palix River is a stream in the U.S. state of Washington. Its tributaries include three forks, North, Middle, and South Fork Palix River, as well as the Canon River. The river's length, including the Canon River, its longest tributary, is approximately ....

, Bear River

Bear River (Washington)

The Bear River is a river in the U.S. state of Washington. Its upper reach is known as Bear Branch.-Course:The Bear River, or Bear Branch, originates just north of the mouth of the Columbia River in the Bear River Range and Willapa Hills. It flows generally north and west, emptying into the...

, Naselle River

Naselle River

The Naselle River is a river in the U.S. state of Washington.-Course:The Naselle River originates in the Willapa Hills and flows generally west, passing the community of Naselle before emptying into the southern part of Willapa Bay....

, Grays River, and Elochoman River

Elochoman River

The Elochoman River is a tributary of the Columbia River, in the U.S. state of Washington. It is about long.The river's name comes from the name of a Cathlamet village.-Course:...

, among others.