Cats in the United States

Many different species of mammal can be classified as cats (felids) in the United States. These include domestic cat (both house cats and feral), of the species "Felis catus"; medium-sized wild cats from the genus "Lynx"; and big cats from the genera "Puma" and "Panthera". Domestic cats vastly outnumber wild cats in the United States.
Prehistoric cats.
At least 67 species of sabertoothed cats existed in North America between 42 million and 11 thousand years ago before going extinct. Their disappearance can be attributed to both the changing climate at the end of the Ice Age and the appearance of humans in the Americas.
Some prehistoric animals referred to as "saber-toothed cats" were in fact marsupials and not cats at all, but called such because of their resemblance to true felines with large canine teeth.
Big cats.
Two main species of big cat once inhabited the United States. One is the jaguar ("Panthera onca"), which is related to many species of big cat found on other continents. Though there are single jaguars now living within Arizona, the species has largely been extirpated from the United States since the early 20th century, although it is found throughout most of South America, its territorial limit being lands further south than northern Argentina.
The other North American 'big cat' is the cougar ("Puma concolor"), which is also known as the puma, mountain lion, catamount, and many other names. Despite weighing 70 kg. (150 lbs) on average and being called a 'mountain lion,' the cougar is not a member of Panthera and is more closely related to the domesticated cat than it is to lions. 
Cougars can be found throughout South America, Mexico, the United States and Canada. Though they may have been more evenly distributed in the United States and Canada (as far north as the southern Yukon border), their populations are currently highest in the western states and provinces respectively. However, western (and possibly southern) cougars are migrating and being encountered more frequently in ranges where the eastern cougar was previously extirpated and declared extinct. This includes the US mid-west and east coast, and central and eastern Canadian provinces. Populations of cougars in Florida have always been continuous and well known.
Wild cats.
Three mammal species in the United States are referred to as "wild cats": the ocelot, the Canadian lynx, and the bobcat. However, none of these animals belong to "Felis", the genus of the wildcat proper and the domestic cat. The ocelot is in the genus "Leopardus", small spotted cats that mostly inhabit Middle and South America, while the lynx and bobcat are both in the genus "Lynx".
A smaller cat than any of the above, the Jaguarundi ("Herpailurus yagouaroundi"), although mostly found in Central and South America, also occurs near the lower Rio Grande Valley in the southern tip of Texas. Being a near relative of the American cougar, the Jaguarundi is more closely related to true wildcats then the other cats mentioned here.
Domestic cats.
The domestic cat, "Felis catus" or "F. silvestris catus", is a popular pet, with an estimated 93.5 million cats kept as pets; about one third of all households in the United States keeping at least one. Eighty-seven percent of owned cats are spayed or neutered
The Centers for Disease Control and Prevention does not require a certificate of health for cats brought into the United States, but cats are subject to inspection at ports of entry and may be denied entry. Cats must be quarantined regardless of place of origin when brought into Hawaii and Guam.
Organizations.
Various organizations using the term Society for the Prevention of Cruelty to Animals (SPCA) and in United States all organizations using the name SPCA are independent; there is no umbrella organization. Some of the more notable organizations include:
The National Cat Groomers Institute of America is an organization devoted to training and certifying people in the grooming of cats. Headquartered in Greenville, South Carolina, it was founded in 2007 by Danelle German, the organization's current president.
"Cats Indoors!" is a public education campaign by American Bird Conservancy and supported by the National Audubon Society and other conservation organizations to encourage control of cats in order to protect birds from predation by cats. The objective of the conservancy's campaign is that all domestic cats should be kept safely indoors.