1. The Great Plains covers much of the central United States, portions of Canada and Mexico. The 100th meridian west is denoted with the red line.

2. The Background of the 1st Transcontinental Railroad
prior to 1869 the only two ways to reach the West coast were to move overland by wagon train that took months, or to sail around the bottom of South America (Cape Horn) and north to present-day California.
The distance and time necessary to get from the East coast to the West coast made it necessary to find a faster, cheaper, and less dangerous way for settlers to move west.
The debate over a transcontinental railroad raged between the North and South before the Civil War.
Everyone agreed that a shorter time than the months necessary to travel around Cape Horn or to travel 2,000 miles overland across desert, mountains, and through Indian country was needed. Only the route could not be agreed upon.
The southern states wanted a southern route while the north wanted a northern route.
In 1862, once the South pulled out of the Union, Congress was able to decide on a route from Omaha to Sacramento.
Two railroad companies, the Central Pacific, building from the west to the east, and the Union Pacific, building from east to west, met at Promontory Point, Utah in 1869.
The migration (moving from one place or location to another) westward was accelerated by the railroad, making it possible to travel long distances in hours and days, not weeks and months.

4. The ceremony for the driving of the golden spike at Promontory Summit, Utah, May 10, 1869.

5. The buffalo is a great symbol and great being to the Plains people because it's really their staff of life and even more than that. The Plains Indians had developed their cultures, communities and way of life around the buffalo. At the utmost, the 24 to 28 Plains tribes had figured out how to use the buffalo in 52 different ways for food, supplies, war and hunting implements, etc.
And so, the hooves, for example, are boiled to use as glue. The hump back is, that part of the buffalo is really kind of sturdy, and so it's used for making shields, the hides for making a teepee, for example. It took about 12 to 14 hides to do that. The buffalo was indeed plentiful and was the most important natural resource to the Plains Indians.

6. In 1800, the best estimates show between 30 million and 40 million buffalos in the Great Plains. By 1902, there were approximately 750 in the entire U.S.
Buffalo hunting in the early 19th century by nomadic plains Indian tribes may have been sustainable, but when the buffalo fur trade exploded in the middle decades of the century, buffalo populations may have begun decreasing.

7. Illustration from Harper’s Weekly: A dead buffalo Hide.
Image from Kansas State Historical Society. “Buffalo Bill” Cody. Indian fighter, buffalo killer, showman and maker of the Western myth.
Illustration from Harper’s Weekly: A dead buffalo
Hide.

8. American Indian’s Way of Life-following the roaming buffalo herds was a part of American Indian’s culture that they did not want to give up

9. To native American Indians, buffalo represent their spirit and remind them of how their lives were once lived, free and in harmony with nature.