Traveling, so I'll be distracted from the Washington landscape.
The cone is called Big Grassy Butte and is located in eastern Idaho. It is in an area of low cones and lava fields of mostly basalt associated with the Yellowstone Hot Spot. This area does not have the continental crust component that makes the Yellowstone Caldera so explosive. Big Grassy Butte rises about 150 feet above the surrounding plain and a somewhat smaller than average irrigated crop circle is farmed in its crater.
Google Aerial Location HERE.