How did Colorado get its nickname and why?

Answer:
On August 2, 1876, 28 days after the Centennial of the United States, US President Ulysses S Grant signed a proclamation admitting the State of Colorado to the Union as the 38th State and earning it the nickname - Centennial State.
First answer by ID1156573192. Last edit by ElleJay. Contributor trust: 35 [recommend contributor recommended]. Question popularity: 3 [recommend question].