I didn't say a deer. It was much smaller than a deer. That being said, here's a little lesson. Mountain lions are actually cougars, which is the most widespread large mammal in the western hemisphere. It ranges from canada deep into south america (all different subspecies, but all the same cat). Here in America we have three subspecies. North American COugar, Eastern Cougar, and FLorida Panther. The United States Fish and WIldlife Service protected both the Eastern COugar and the florida PAnther until the subspecies were combined (not sure what year they combined the subspcies...there used to be around 36 subspecies but they have been combined down to six subspecies now I believe). THere has been a confirmed killing near chicago, which was genetically tested and proven to have come from the black hills (year 2000 I think). SO yes, they are east of the great mississippi. If they are in chicago of course they could be east. Just a matter of time, we'll be seeing them just like we see bears here in north east ohio fairly often now.
-Jake