Congress set the 100th meridian as an early goal for the Union Pacific when it chartered the first transcontinental railroad, and construction crews reached it here, at what became Cozad, in early October 1866 (the marker says October 5; Union Pacific says October 6). On October 26, 1866, the "Great Excursion from Wall Street to the 100th Meridian" brought about 250 notables, including congressmen, financiers, railroad officials and newspapermen, here on the first passenger train to run west of the Missouri River.

The meridian is also a natural dividing line. Geologist John Wesley Powell described it in 1879 as the boundary between the humid East and the arid West, where farming depends on irrigation. The Cozad chapter of the Daughters of the American Revolution placed the first stone monument in 1933; the current marker stands at U.S. 30 and North Meridian Avenue, near the old Union Pacific depot. Part of the Great Platte River Road along U.S. 30.

Information: Cozad Area Chamber of Commerce, 308-784-3930.