Having once inhabited most of the United States, mountains lions were extirpated from eastern and central portions of our country by the early 20th Century; an exception was the Florida panther, which managed to survive in the dense vegetation of the Everglades and adjacent cypress swamps. Throughout most of the 1900s, the easternmost populations of cougars (other than the Florida panther) were in West Texas and in the Black Hills of western South Dakota.
However, over the past decade, sightings of mountains lions have increased signficantly across the American Midwest. Almost all of the confirmed cases have been males, presumably banished from their home range by other dominant males; indeed, cougars are territorial and field studies have revealed that the home range of adult males is in the neighborhood of 100-300 square miles. While 5 mountain lions inhabited the Pine Ridge Escarpment of western Nebraska in 2004, 30 were documented by 2011, including females and cubs. Sightings in Kansas, Missouri, Iowa, Minnesota and Wisconsin have involved male cougars that are thought to have wandered eastward from South Dakota and western Nebraska (though some may have arrived from Colorado via the Arkansas River corridor). One famous case involved a male that wandered through Minnesota and Wisconsin in 2009-2010 and ended up getting killed in Connecticut in 2011. Here in Missouri, there have been at least 29 cougar sightings since 1994, though, in some cases, multiple sightings of the same cat may have occurred. Since mountain lions are secretive and primarily nocturnal, an accurate estimate of Midwest wanderers is very difficult to obtain and it is likely that more pass through this region than some human residents might care to imagine; on the other hand, livestock loss to cougars has been minimal since these travelers seem to favor small mammals and the occasional deer.
Of course, unless females begin to follow the nomadic males from mountainous areas of the West, breeding populations will not become established in the Heartland. The increasingly common sightings in recent decades surely reflects the growth of human populations throughout the Mountain West, depriving these predators of their natural habitat and forcing males to head east, following river channels across the Great Plains. Any excitement associated with the opportunity to observe these magnificent cats in the Midwest is tempered by the knowledge that we have driven them from their modern homeland and that they are returning to an ancient homeland that has forever changed. Whether they will be welcomed or persecuted remains to be seen.