Both Bald cypress (or Pond cypress) and Dawn redwood drop their needles in the fall (actually, usually the end twigs are deciduous, too). Location would not be much help, as both are hardy in the Chicago area, and Bald cypress is native in Illinois only at the southern tip of the state. The way to know the difference in "young" trees like this is the twig arrangement:
--- Bald cypress is alternate.
--- Dawn redwood is opposite.
Sometimes Bald cypress may
seem opposite, but even so, there will always be some that are clearly alternate.
Dawn redwood is
always opposite, no exceptions.
Bald cypress:
https://www.google.com/imgres?...
Dawn redwood:
https://www.google.com/imgres?...