CIRCUMSTANCES UNDER WHICH THIS RECONNAISSANCE WAS CONDUCTED, 
The present reconnaissance was pursued as the result of the reconnaissance of the northern 
frontier Pacific railroad route, which extends from St. Paul, Minnesota, to Puget Sound. The 
extreme difficulties of that route gradually led to the necessity of seeking other location by 
detour, and eventually to the exploration of the present line. 
This report may, therefore, be considered as offering a general recapitulation of the features 
of country between latitude 49 north and the Salt Lake City, and between the southernmost 
point of Lake Michigan and Puget Sound, regarding railway location as affected by the peculiar 
character of the project of a railroad to the Pacific. 
The difficult nature of the western mountainous country traversed by the northern route had, 
in a measure, destroyed its character before reaching the Cascade Mountain range of the Pacific 
coast. It became necessary either to tunnel that mountain range at an almost impracticable 
pass, to procure passage to the ocean, or to surrender the line of direction, and to deflect so far 
towards the south as to pass through the great valley of the Columbia river. This detour south, 
which involved an increased distance of 140 miles, was at once decided to be the preferable 
line. 
The valley of the Columbia was of remarkable nature ; the waters of the interior had there 
perforated the great chain of the Sierra Nevada and Cascade Mountain range, and flowed to 
the ocean over the nearly level bed of a navigable stream. No engineer of practice in railway 
construction could fail to be impressed with the strength of the line. It was the only natural 
pass to the ocean from the great interior of the American continent. Danger from snow, a 
most formidable enemy to encounter upon the steep grades and in the deep cuttings of a mount¬ 
ain route, was wholly avoided. A navigable stream afforded means of transportation for 
weighty material. The work of construction could take place from the Pacific as well as from 
the Atlantic side of the continent. Large forces of laborers could be employed along the whole 
length of an open route, and speedily grade and perfect the road. And when the study of the 
question of detour reached the consideration of the merits of a rival route, then this great pass 
and valley became exponents in a discussion which destroyed all claims of the extreme northern 
frontier line to further attention. It occupied a position to command and unite the grandest 
interests, and to place such weight upon the scale of public opinion (fixed on the merits of all 
the national routes to the Pacific) as evidently to do much toward ruling the selection. Rail¬ 
roads from the southern waters of Lake Michigan were already in construction west, as the 
continuation of the great ramification of the net-work of iron which had so aided and developed 
the resources of the northern and middle States. All the important interests of those sections, 
and the capital invested in those lines, concentrated and fixed their united strength upon a 
route to the Pacific through a healthy country, practicable of solution as a problem, in the ques¬ 
tions of construction which arose in the application of labor and the transportation of supplies. 
It was evident that the wealth and mineral resources of California first drew public attention to 
the question of a railway across the American continent. This project, aided so long by the 
labors of Whitney and his associates, received little, encouragement until the immense trade of 
the gold regions, and the important interests therewith connected, added their strength to its 
development. Therefore, if but one road were constructed to the Pacific, it would seek the bay 
of San Francisco as a terminus. 
