The decade from 1850 to 1860 saw a very rapid growth in the steamboat business of the Missouri River. The stream of emigration across the plains continued practically unchecked. Settlement was rapidly filling up the lower valley of the river, and by 1856 had reached as far as Sioux City, and all the modern towns below that point had commenced their existence. Government exploration was being pushed with vigor in all directions into the country beyond. The Indians were becoming restive under the pressure of settlement; their annuities were increasing, and the presence of troops in all parts of their country was becoming more imperative. The long Indian wars of the Missouri Valley were beginning. [Sidenote: STEAMBOAT STATISTICS.] All these developments had their effect upon the steamboat traffic of the Missouri River, for that stream was the one great transportation route into the heart of the West. Some idea of the magnitude of the business may be gleaned from the records of the times as published in the newspapers along the river. In the year 1858 there were 59 steamboats on the lower river and 306 steamboat arrivals at the port of Leavenworth, Kan. The freight charges paid at that point during the season amounted to $166,941.35. In 1859 the steamboat advertisements in the St. Louis papers showed that more vessels left that port for the Missouri River than for both the upper and lower Mississippi. In 1857 there were 28 steamboat arrivals at the new village of Sioux City before July 1. There were 23 regular boats on that part of the river, and their freight tonnage for the season was valued at $1,250,000. The period from 1855 to 1860 was the golden era of steamboating on the Missouri River. It was the period just before the advent of the railroads. No other period before or after approached it in the splendor of the boats. All the boats were sidewheelers, had full-length cabins, and were fitted up more for passengers than for freight. It was an era of fast boats and of racing. It was the heyday of that most important personage, the Missouri River pilot.[33] [Sidenote: PROGRESS UP THE RIVER.] While this rapid development of traffic on the lower river was going on, the American Fur Company was laying its plans to carry steamboat navigation to Fort Benton. We have elsewhere told how the _Assiniboine_ in 1834 reached a point near the mouth of Poplar River, a hundred miles above the Yellowstone, and being caught by low water, was compelled to stay there all winter. For the next nineteen years this remained the farthest point reached by steamboats. In 1853 the _El Paso_ went about 125 miles further, to a point five miles above the mouth of Milk River. El Paso point, as this place came to be called, marked the limit of steamboat progress up the river for the next six years.