Port Isabel, Sonora

It was founded to support the increased river traffic caused by the gold rush that began in 1862 on the Colorado River and the Yuma Quartermaster Depot newly established in 1864 to support the Army posts in the Arizona Military District.

[1] By 1867, Port Isabel, was situated on Port Isabel Slough whose mouth lay to the east of the main channel of the Colorado River on its channel east of Montague Island about 21⁄2 miles from its entrance, at the first good landing place, the shores below being of very soft mud.

Port Isabel, served as a location for repairing the river steamers and barges at a location about 2 miles above Port Isabel on what was called Shipyard Slough that became the site called Ship Yard, which had a few frame buildings, a dry dock and a ship way where steamboats could be constructed or repaired.

[2] The arrival of the Southern Pacific Railroad in Yuma in 1877 signaled the end of Port Isabel.

In 1877, George Alonzo Johnson sold his Colorado Steam Navigation Company to the Southern Pacific Railroad.