EarthSky published an infographic earlier in May which describes the hottest and coldest temperatures on Earth. You can find it here. The hottest place in the US? Death Valley CA, with a record high temperature of 134.1 F. I was disappointed to see that they did not list the coldest record for the US though.
[Note that the original source of the infographic is http://gbenergysupply.co.uk/blog/2015/05/11/hottest-and-coldest-places-on-earth.php.]
Fortunately, Wikipedia has a better list at http://en.wikipedia.org/wiki/List_of_weather_records. The coldest in Alaska was -80 F in Prospect Creek and the coldest in the lower 48 states is -70F at Rogers Pass, Montana.