How did Colorado get the nickname the Centennial State?

Because Colorado became a state when America was celebrating the centennial (100th birthday) in 1876

from the spanish from the spanish

Colorado became a state in 1876. In that year, America was celebrating its centennial (or its 100th birthday) and Colorado was the only state to officially become a state in that year

Colorado.

Because Colorado officially became a state in 1876, the year of America's 100th birthday, more known as "centennial."