Topics: The God Whisperers
During the prehistoric period , the land that would become Portland was flooded after the collapse of glacial dams from Lake Missoula , located in what would later become Montana. These massive floods occurred during the last ice age and filled the Willamette Valley with 300 to 400 feet (91 to 122 m) of water. 
Between 1900 and 1930, the population of the city tripled from nearly 100,000 to 301,815.  During World War II, it housed an "assembly center" from which up to 3,676 people of Japanese descent were dispatched on concentration camps in the heartland. The Pacific International Livestock Exposition operated from May through September 10, 1942 processing people from the city, northern Oregon, and central Washington. 
Portland is located 60 miles east of the Pacific Ocean at the northern end of Oregon 's most populated region, the Willamette Valley. Downtown Portland straddles the banks of the Willamette River , which flows north through the city center and consequently separates the east and west neighborhoods of the city. Less than 10 miles from downtown, the Willamette River flows into the Columbia River , the fourth-largest river in the United States, which divides Oregon from Washington state. Portland is about 100 miles upriver from the Pacific Ocean on the Columbia.