Construction of the Union Pacific track reached the 100th Meridian on 26 October 1866 and a grand ceremony was held near this spot with over 250 notables in attendance on the first passenger train west of the Missouri River.
In 1879, John Wesley Powell, in his Geological Report, recognized the 100th Meridian as the natural demarcation line extending northward from the western shore of the Gulf of Mexico. Evaporation from the Gulf supplies rain water east of this line, and the insufficient rainwater west of the line is from the Pacific. This is where the humid East meets the arid West.
The photo on the right is along the old highway west of town at the site of the actual 100th Meridian.