Cottonwood Island was important as a source wood and of fuel for steamboats on that river and for the early mills and mines in El Dorado Canyon.

John Ross Browne described it in his 1869 report on the Colorado River: Cottonwood Island appears in the 1875 Topographical Sketch showing the Outward and Inward Route of a Party, while examining as to the practicability of a Diversion of the Colorado River for Purposes of Irrigation, from an annual report by 1st Lt. G. M. Wheeler, Corps Of Engineers.

Wood was cut up by the Mohave and provided as fuel to steamboats traveling the river past Cottonwood Island or as timber for the mines.

But such traffic only could occur during the high water months, the only time the steamboats would navigate the rapids and shallows of this upper reach of the Colorado.

In late 1863 when the first stamp mill was established at the mines, ore was no longer carried down river in sufficient volume and the steamboats did not come as often.