Nevertheless, I just did a quick google search and came up with quite a few instances of place names that claim "Kill" is a derivative from Dutch meaning stream or river. (put in kill +river +dutch + meaning and see what comes up.) There must be something to it.

It's possible that it's not a word in common Dutch use now, but at one time was common enough to get transferred to many place names. It may even have been from some sort of local dialect that made it to America but was not very strong back in it's native home.

One of my coworkers is Dutch, and she's quite knowledgeable about languages. I plan on asking her about it next time I see her. You've all made me curious about it now.

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...And that, my liege, is how we know the Earth to be banana-shaped. --Sir Bedevere