A few reasons it grew so fast and became a major trade center was:

1. It was selected as the West Coast terminal for The Petonia, the U.S. mail steamer.
2. The salmon & lumber industries
3. The 1st transcontinental railroad in 1883, linking Portland with the East Coast, making it a major trade center.
4. After the Gold Rush of '49, it became a boomtown, carrying wheat and other commodities to and from California and other ports around the globe. At that time, Portland had the longest wheat terminal in the world, and currently the largest on the west coast. Millions of bushels of wheat.
5. A few years after that, cargo carrying international shipping lines found Portland 97 miles up river, opening up a full spectrum of international trade that funneled itself through Portland.
6. Finally, "The Great Plank Road" - First planks for the Canyon Road connecting Portland with the rich Tualatin Valley were laid near this spot in September 1851, helping to beat other nearby towns for dominance. As a community effort it brought farm produce to our docks and established Portland as a port and market for the Old Oregon Country.