Clear Creek County , in the north-central part of Colorado on the Front Range west of Denver.
"Clear Creek, South Boulder Creek and their tributaries were the sites of the first significant placer gold discoveries in Colorado.....In 1922 the first attempt was made to recover placer gold as a by-product from the sand-and-gravel plants along Clear Creek below Golden, and since that time gold production from this sources has gradually increased. Since 1951 these plants have produced the bulk of the state's placer gold production from the treatment of large quantities of low-grade gravels." - Ben Parker Quarterly of the Colorado School of Mines: Gold Placers of Colorado - Book 1 of 2 [Pg. 63-64]