I asked this question over at /r/answers and was told that this might be better suited for historians. So...
It's usually a count who's reigning over counties, who's somewhere on the lower levels of a classic feudal monarchy, right? So why is it that the nation born as a republic even has "counties"? I guess it's a colonial thing, but I still find it weird that it is kept to this day.
You might be interested to the answer I provided to a similar question a few months ago: https://www.reddit.com/r/AskHistorians/comments/61leij/why_is_the_united_states_divided_up_into_counties/dfftdsl/