American crocodiles live in Southern Florida and through much of the Caribbean, Mexico, Central America, and the northern and northwestern parts of South America. 
How do you tell American alligators and American crocodiles apart?
So many times I've heard someone trying to figure out if an animal they're looking at is a crocodile or an alligator. This is common in the USA, where we have both living wild in the state of Florida. They are also both commonly found in zoos.
I hear some say, "You can tell by looking at their teeth," and others say, "You can tell by their color." So what’s the truth?
Here are the main differences between American alligators and American crocodiles:
(1) The first difference is the easiest to quickly look for. It's the shape of the snout. Alligators have a more broad u-shaped mouth and nose, and crocodile snouts go to more of a point and are v-shaped. 
(2) Crocodiles have many teeth showing when their mouths are closed, particularly the fourth tooth on the lower jaw on either side.  Alligators never have teeth from their lower jaw sticking out when their mouths are closed.
(3) Crocodiles tend to be lighter in color.
(4) Crocodiles tend to be considerably more aggressive. 
(5) Crocodiles will go into saltwater at times, and alligators never do. 
(6) Crocodiles have more webbing on their hind feet.
When it’s really hard to tell with certain individuals, the best way to tell is the fourth tooth sticking up on crocodiles (#2 above). Although, maybe it’s best to not know if it requires getting close to those teeth to find out!
The largest crocodile species, the saltwater crocodile, inhabits Australia, Southeast Asia, Indonesia, the Philippines, eastern India, and some of the islands in the western Pacific Ocean. It is the largest reptile species on Earth. They can exceed 20 feet (6 meters) in length.
Crocodiles, alligators, caimans, and gharials are the four types of modern crocodilians, with crocodilia being one of several orders of reptile found on our planet. Alligators and caimans are closely related, and have similarities such as the broader u-shaped snouts. Several species of caiman live in Central and South America.
Alligators are two species, with the American alligator found only in the southern and southeastern USA, and the Chinese alligator found only in eastern China. The Chinese species is considerably smaller than the American species, and they are critically endangered, although extensive efforts are being made to increase their numbers.
Gharials are just one remaining species, and they are unfortunately critically endangered with just a few hundred left. They are native to India, Pakistan, and Bangladesh.
American crocodiles are native to Florida, USA and also Mexico, Central America, and the northern and northwestern parts of South America (Venezuela, Colombia, and Ecuador). Three other crocodile species live within parts of this same area.
Ten other crocodile species live elsewhere in the world through most of Africa, and also in India, Southeast Asia, Indonesia, the northern parts of Australia, the Philippines, and some of the other islands of the Western Pacific. Overall there are fourteen species of crocodile. Of those, four are critically endangered.
The smallest crocodile species is the dwarf crocodile of western Africa, which rarely reaches six feet (1.8 meters). Chinese alligators are only slightly larger, with lengths of seven feet (2.1 meters) being rare.