Geography of Cowlitz County, Washington

Cowlitz County, situated in the southwestern part of the state of Washington, is renowned for its diverse geography, ranging from majestic mountains to scenic rivers and lush forests. From its stunning natural landscapes to its vibrant communities, Cowlitz County offers a unique blend of outdoor recreation, cultural heritage, and economic opportunities. In this comprehensive exploration, we will delve into the geography, climate, rivers, lakes, and other notable features that define Cowlitz County.


According to Shoe-Wiki, Cowlitz County spans an area of approximately 1,147 square miles (2,973 square kilometers) and is located along the banks of the Columbia River. It is bordered by several other counties, including Lewis County to the north, Skamania County to the east, and Clark County to the south. The county’s landscape is characterized by its diverse topography, which includes mountains, valleys, and lowlands.

The geography of Cowlitz County is shaped by several major geological formations, including the Cascade Range to the east and the Coast Range to the west. These mountain ranges contribute to the county’s rugged terrain, with elevations ranging from sea level along the Columbia River to over 7,000 feet (2,134 meters) in the Cascade Mountains.

The county seat of Cowlitz County is the city of Kelso, while other notable communities include Longview, Castle Rock, and Woodland. These towns and cities are situated along the county’s network of roads and highways, which provide access to the surrounding countryside and neighboring regions.


Cowlitz County experiences a marine west coast climate, characterized by mild, wet winters and warm, dry summers. The region’s climate is influenced by its proximity to the Pacific Ocean and the Cascade Mountains, with weather patterns shaped by maritime air masses and prevailing westerly winds.

Summers in Cowlitz County are typically warm and sunny, with average temperatures ranging from the mid-60s to mid-70s Fahrenheit (around 18 to 24 degrees Celsius). Heatwaves are rare but can occur during periods of high pressure, with temperatures occasionally exceeding 90 degrees Fahrenheit (32 degrees Celsius). Rainfall is infrequent during the summer months, leading to dry conditions and increased wildfire risk.

Winters in Cowlitz County are generally mild and wet, with average temperatures ranging from the mid-30s to low 40s Fahrenheit (around 1 to 5 degrees Celsius). Rainfall is common, particularly in the lowlands and valleys, where several inches of rain can accumulate each month. Snowfall is infrequent in the lower elevations but can occur in the mountains and higher elevations, where several feet of snow can accumulate throughout the winter months.

Spring and fall are transitional seasons in Cowlitz County, characterized by mild temperatures and changing weather patterns. Spring brings the blooming of flowers and the greening of the landscape, while fall showcases the vibrant colors of changing leaves and the harvest of agricultural crops.

Rivers and Streams:

Cowlitz County is home to several rivers, creeks, and streams, which provide valuable water resources and support diverse ecosystems. The county is situated within the watershed of the Columbia River, one of the largest rivers in the United States, which flows along the southern border of the county.

The Columbia River and its tributaries provide habitat for a variety of fish and wildlife, as well as opportunities for fishing, boating, and water sports. Other notable waterways in Cowlitz County include the Cowlitz River, Coweeman River, and Kalama River, which flow through the county’s scenic valleys and forests.

Lakes and Reservoirs:

Cowlitz County is home to several lakes and reservoirs, which provide recreational opportunities and scenic beauty for residents and visitors alike. These include Silver Lake, Lake Sacajawea, and Mayfield Lake, which offer opportunities for fishing, boating, swimming, and picnicking.

Parks and Outdoor Recreation:

Cowlitz County is home to several parks, natural areas, and outdoor recreation opportunities that showcase the region’s natural beauty and cultural heritage. These include:

  • Mount St. Helens National Volcanic Monument, located in the eastern part of the county, which is a protected area that preserves the aftermath of the 1980 eruption of Mount St. Helens. The monument features hiking trails, interpretive exhibits, and scenic overlooks, allowing visitors to explore the volcanic landscape and learn about the geology and ecology of the area.
  • Mount Rainier National Park, located in the northeastern part of the county, which is a designated wilderness area that showcases the majestic beauty of Mount Rainier, the highest peak in the Cascade Range. The park offers hiking trails, camping facilities, and ranger-led programs, allowing visitors to experience the diverse ecosystems and stunning vistas of the mountain.
  • Seaquest State Park, located along the banks of Silver Lake, which is a scenic park that offers camping, picnicking, and hiking opportunities in a peaceful woodland setting. The park also features a boat launch, fishing pier, and interpretive center, providing opportunities for outdoor recreation and environmental education.

Historical Landmarks:

Cowlitz County is steeped in history and is home to several historic landmarks and sites that showcase its rich heritage. These include:

  • Cowlitz County Historical Museum, located in Kelso, which is a cultural institution that preserves and promotes the history and heritage of Cowlitz County. The museum features exhibits, artifacts, and photographs that highlight the region’s Native American history, pioneer settlement, and industrial development.
  • The Nutty Narrows Bridge, located in Longview, which is a quirky landmark that crosses Olympia Way and is famous for its resident squirrel population. The bridge was built in 1963 to provide a safe crossing for squirrels in downtown Longview and has become a beloved symbol of the city’s unique charm.
  • The Mount St. Helens Visitor Center, located near Castle Rock, which is an interpretive center that provides information about the eruption of Mount St. Helens in 1980. The center features exhibits, films, and interactive displays that educate visitors about the volcanic eruption and its impact on the surrounding landscape and communities.


In conclusion, Cowlitz County, Washington, offers a wealth of natural beauty, outdoor recreation opportunities, and historical landmarks for residents and visitors to enjoy. From its scenic rivers and lakes to its majestic mountains and lush forests, the county’s geography reflects its diverse landscapes and rich natural heritage. Whether exploring national parks, hiking in the mountains, or learning about the region’s history, Cowlitz County has something to offer for everyone. With its stunning landscapes, rich history, and vibrant communities, Cowlitz County is truly a gem of the Pacific Northwest.