Colorado’s nickname, “The Centennial State,” comes from it being admitted to the Union in 1876 – the nation’s 100th anniversary. But statehood only came after many, many tries.
After becoming its own territory in 1861, Colorado could have actually become a state as early as 1864, with Republican senators welcoming the idea for more votes to help President Abraham Lincoln’s re-election campaign. But Colorado voters said no.
They tried again in 1865, but President Andrew Johnson vetoed their statehood. It took a decade, but Colorado was finally admitted by President Ulysses Grant on Aug. 1, 1876 — 22 days after the Centennial.
– Staff Reports, The 100 Companies