>>Washington, DC is not really a state.
>
>I have District of Columbia as a State. That one is correct right?
>
>I also have Washington in the list of States. So, if I understand correctly, that one should be removed. Is that correct? If yes, then, it would bring it down to 51. Thus, I would have a missing State. Can you clarify all this?

No, the Washington is indeed a state. However, the District of Columbia is not a state. But I do not see how should we define it otherwise, so I would think you need to keep everything as you currently have.