I don't know about Colorado, but apparently in Ohio it's needed "to earn the highest level of certification". https://www.teachingdegree.org/states/ohio/#:~:te

I don't know about Colorado, but apparently in Ohio it's needed "to earn the highest level of certification". https://www.teachingdegree.org/states/ohio/#:~:text=Generally%2C%20obtaining%20a%20regionally%20accredited,standard%20teaching%20requirements%20in%20Ohio.&text=Though%20a%20master's%20degree%20is,the%20highest%20level%20of%20certification https://www.teachingdegree.org/states/ohio/#:~:text=Generall....