Boise’s population growth amplified by pandemic, migration data shows Californians accounted for 10,073 of last year’s new moves into the Boise area. That was up 27.5% from the year before, which saw roughly 7,900 Californians move. Author: Paul Schwedelson (The Idaho Press) Published: 3:32 PM MDT May 6, 2021 Updated: 3:32 PM MDT May 6, 2021 BOISE, Idaho — : This article was originally published by The Idaho Press. As the Treasure Valley’s population keeps growing, the abnormality of 2020 only amplified the trends fueling the area’s boom. The No. 1 state sending newcomers to the Treasure Valley during the pandemic continued to be the state of Idaho itself, followed by California and Washington.