Jawbone, the company that was able to map earthquake intensity in California a few months ago by noting which wearers of their device woke up during an earthquake,
is at it again.
Here is their US map of when users go to sleep. A really cool thing shows that people on the eastern side of time zones go to bed earlier than those on the western side, presumable because it gets dark in the East sooner.
Brooklyn is the only county in the US that goes to sleep (on average) after midnight.
I wish I could imbed the interactive map, but I don't know how. Click the link above.
Here is a screenshot of the static map.
Edit: And here are the hours of sleep each night
