Free roaming cats:
Cats love to roam the outdoors, and some cats prefer to live outdoors. They are commonly seen wandering around neighborhoods and sometimes it’s hard to know if a cat has an owner (free roaming) or if it is a stray or feral. Sometimes we aren’t sure if we should capture these cats and take it into the vet or humane society, but there are ways to tell a difference between the three classifications and help you decide whether you should attempt to catch it or leave it alone. A free roaming cat is usually friendly and appears well fed and well groomed as well as wearing a collar and identification tags. If this cat is friendly and appears to be healthy, the best thing to do is leave it alone. Don’t befriend them or feed them unless you want them coming around more often.
Stray Cats:
Stray cats are cats that were once pets, but have been abandoned or lost. Some may appear friendly and may even approach you for attention and food. Some might be feral at first, but once you befriend them, you’ll find that they enjoy human touch and companionship. If you find a stray cat, the best thing to do is catch it and attempt to find his/her original family; especially if the cat appears to be weak and not in good shape or health. If no one claims the cat and you’d rather not keep it, you can try re-homing it yourself or give it to a rescue or shelter.
Feral cats: 
When people abandon their domesticated cats, these cats can learn to live on their own and become feral. They produce feral kittens if not spayed or neutered and these kittens usually live their entire lives without human contact; thus making them extremely shy and cautious around humans. Feral cats often live in a group, also called a colony, but may roam alone, especially if the food is scarce. Feral cats are much harder to get close to, due to how cautious they are, and may even be very unfriendly. The best thing to do is set up a humane trap to catch them in before taking them to the vet or shelter.

Here is a link providing more information, as well as tips and suggestions, about these three classes of cats and what to do if you find one:

http://www.aspca.org/Pet-care/virtual-pet-behaviorist/cat-articles/stray-and-feral-cats 

Free roaming cats:

Cats love to roam the outdoors, and some cats prefer to live outdoors. They are commonly seen wandering around neighborhoods and sometimes it’s hard to know if a cat has an owner (free roaming) or if it is a stray or feral. Sometimes we aren’t sure if we should capture these cats and take it into the vet or humane society, but there are ways to tell a difference between the three classifications and help you decide whether you should attempt to catch it or leave it alone. A free roaming cat is usually friendly and appears well fed and well groomed as well as wearing a collar and identification tags. If this cat is friendly and appears to be healthy, the best thing to do is leave it alone. Don’t befriend them or feed them unless you want them coming around more often.

Stray Cats:

Stray cats are cats that were once pets, but have been abandoned or lost. Some may appear friendly and may even approach you for attention and food. Some might be feral at first, but once you befriend them, you’ll find that they enjoy human touch and companionship. If you find a stray cat, the best thing to do is catch it and attempt to find his/her original family; especially if the cat appears to be weak and not in good shape or health. If no one claims the cat and you’d rather not keep it, you can try re-homing it yourself or give it to a rescue or shelter.

Feral cats:

When people abandon their domesticated cats, these cats can learn to live on their own and become feral. They produce feral kittens if not spayed or neutered and these kittens usually live their entire lives without human contact; thus making them extremely shy and cautious around humans. Feral cats often live in a group, also called a colony, but may roam alone, especially if the food is scarce. Feral cats are much harder to get close to, due to how cautious they are, and may even be very unfriendly. The best thing to do is set up a humane trap to catch them in before taking them to the vet or shelter.

Here is a link providing more information, as well as tips and suggestions, about these three classes of cats and what to do if you find one:

http://www.aspca.org/Pet-care/virtual-pet-behaviorist/cat-articles/stray-and-feral-cats