The California Mountain Region takes up about half of California. It has two mountain ranges, the Cascade Range and the Sierra Nevada Range. California mountain ranges were formed millions of years ago by earthquakes, volcanoes, and glaciers. Climate: The coastal side of the mountain region is moist, cool, and foggy. California Geography: The Land Geography and Landforms of California. Find an overview of California geography, topography, geographic land regions, land areas, and major rivers.. Access California almanac, furnishing more details on the state geography, geographical and land regions, climate and weather, elevation, land areas, bordering states, and other statistical data. Born from the collision and sliding of the Earth's crustal plates, the mountains are home to some of the most unique and rare natural features and ecosystems in the United States. Part of the Transverse Ranges that stretch from the Mojave Desert to the Channel Islands, these mountains are some 46 miles long and eight miles wide.