Is there a dictionary that has city names in it?

The dictionary I have Does not know city names. Des Moines. It will say Des is not a word and Moines is not a word. I am not sure whether it has any geographic names in it. For libre office writer.

The spell checker doesn’t look at context, it just checks if single words are in the dictionary or not. You can use the Language Tool for word groups, and that might have a set of rules for names like Des Moines.