Yes, COLORADO is a Scrabble word!

Letter values in Scrabble US: C 3, O 1, L 1, O 1, R 1, A 1, D 2, O 1.

Is it a valid word?

COLORADO is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a state in west central United States in the Rocky Mountains
a river in Texas; flows southeast into the Gulf of Mexico
an important river in the southwestern United States; rises in the Rocky Mountains of northern Colorado and flows southwest through Utah into Arizona (where it flows through the Grand Canyon) and then southward through the southern tip of Nevada, then forming the border between California and Arizona and finally into Mexico where it empties into the Gulf of California; the main source of water in the southwestern United States

Also: centennial state, colorado river.

Not playable in Scrabble US: CO.