Final answer:
The state with the Cascade Mountains, several active volcanoes, Olympic Mountains, the only US rainforest, the wettest place in the continental US, Columbia Plateau, and Blue Mountains is Washington.
Step-by-step explanation:
The state you are inquiring about is Washington. Washington state is home to the Cascade Mountains, which include several active volcanoes such as Mount Rainier and Mount Saint Helens. It also boasts the only temperate rainforest in the United States, located in the Olympic Mountains. Additionally, Washington encompasses the Columbia Plateau, characterized by the Columbia River, and the Blue Mountains. The state also claims the title for the wettest place in the 48 contiguous states.