The definition of an enclave is multi-dimensional and can consider a mix of geographic, cultural, economic, ethnic, legal, religious and sociological features. Nonetheless, the two fundamental characteristics of enclaves are that they occupy a territory or space and, within these, the inhabitants (or, as least the vast share of them) are distinctive in some way.

Perhaps the best way to illustrate an enclave is through an example of two historically related religious groups: one in the two countries of Canada and the United States and the other in Mexico. One is not a rural enclave, and the other is. In the United States, there are now over 600 Amish communities. Clearly the Amish are distinctive with their horse-and-buggy lifestyle, plain dress and use of the Pennsylvania Dutch language (a variant of German). However, they are not an enclave. Non-Amish Canadian and United States citizens are neighbours to the Amish, sharing the same space and, in all but a few places, vastly outnumber the Amish. The area where the Amish live may have a distinctive flavour, such as ‘eggs for sale, no Sunday sales’ signs and horse droppings on the road, but it is not an enclave.

To the south in the Mexican state of Chihuahua is a related group known as Old Colony Mennonites. They, too, are distinctive from the majority population in that area, which also outnumbers them. However, what qualifies them as an enclave is that they live in segregated communities known as colonies, even though they may travel to a nearby town for supplies, medical care and other services. Similarly, other religious groups related to both Amish and Old Colony Mennonites are the Hutterites of the Great Plains states of the United States and prairie provinces of middle Canada. They also live in segregated colonies, where they communally share most of the property and are sometimes referred as the oldest socialist society in human history, having adopted this lifestyle over 400 years ago.