Eastern Oregon is the eastern part of the U.S. state of Oregon. It is not an officially recognized geographic entity, thus the boundaries of the region vary according to context. It is sometimes understood to include only the eight easternmost counties in the state; in other contexts, it includes the entire area east of the Cascade Range. Cities in the broadest definition include Baker City, Bend, Burns, Klamath Falls, La Grande, Ontario, Pendleton, and The Dalles. Major industries include timber, agriculture, and tourism, with the main transportation corridors consisting of I-84, U.S. Route 395, U.S. Route 97, U.S. Route 26, U.S. Route 30, and U.S. Route 20. Compared to the climate of Western Oregon, the climate of Eastern Oregon is a drier continental climate, with much greater seasonal variations in temperature. Unlike the Willamette Valley, Eastern Oregon receives a significant amount of snow in the winter. Some parts of Eastern Oregon receive fewer than 10 inches (250 mm) of rain yearly, classifying them as deserts. This desert climate is in part due to a rain shadow effect caused by the Cascade Range. Pine and juniper forests cover 35% of Eastern Oregon, much in the mountains that include the Blue Mountains, Strawberry Mountains, Wallowa Mountains, Trout Creek Mountains, Ochoco Mountains, and Steens Mountain. Basalt flows from the Columbia River Basalt Group covered large sections of Eastern Oregon 6 to 17 million years ago. Other landforms include the Alvord Desert, Owyhee Desert, Warner Valley, Deschutes River, Owyhee River, Grande Ronde River, Joseph Canyon, The Honeycombs, and Malheur Butte.