During the period between 1842 and 1855, old Oregon was mostly peopled by immigrants from the Mississippi valley, who came overland. After the completion of the railroad across the Isthmus in 1855, immigrants from near the Atlantic seaboard took steamer at New York City for Aspinwall, crossed the Isthmus by rail, thence to San Francisco by steamer and to Oregon and Washington by sailing craft or steamer. Troubles with Indians between the Missouri and Columbia, of frequence in the later 'fifties, followed closely by the great Civil War period, materially checked the influx of population overland. In fact, not until the completion of the Northern Pacific in 1883, and soon afterward of the Oregon Shortline, did the real development of Oregon and Washington begin. In 1850 there were in old Oregon only 13,000 white settlers, 1049 of whom lived north of the Columbia River; in 1860 Oregon had 52,000, Washington, 11,500; in 1870, Oregon 91,000, Washington 24,000; in 1880, Oregon 175,000, Washington 75,000; in 1890, Oregon 314,000, Washington 349,000. The Northern Pacific Railroad had been completed in 1883, quickly followed by the Oregon Shortline, and Washington had gained nearly fivefold in a decade and had passed her older sister in population. In 1900 Oregon had 414,000, Washington 518,000; in 1910 Oregon had 673,000, with Washington 1,142,000, or a gain by the latter of more than 100 per cent in ten years. Oregon had an assessed valuation of 905 millions and Washington, 1025 millions. Neither had a bonded debt. The Canadian Pacific, Great Northern, Chicago, Milwaukee & St. Paul, Northern Pacific, Oregon Shortline and Southern Pacific railroads had all reached Pacific coast terminals, and in consequence the great Northwest had gained remarkably in population, wealth and volume of trade and commerce. In the Willamette valley the water power afforded by the streams of the Cascades and Coast ranges served to operate the early wood working and flouring mills, the woolen mills and small manufacturing plants, but on Puget Sound it was more economical to operate the saw-mills by steam where the ships could reach the docks easily and quickly. Almost immediately after their arrival at Tumwater, the first American settlers began building a saw-mill and a grist-mill on the bank of the Des Chutes River. The irons were bought from the Hudson's Bay Company and the millstones were made from a large granite boulder near by. Both mills were run by water power. A few other small mills were constructed elsewhere on the Sound, but all were financial failures.