Have you ever browsed through active listings and noticed terms like housing for older persons or 55 or older and wondered what it meant? These listings belong to age-restricted communities that exist across the country.

An age-restricted community, which is also referred to as an active adult community or a 55+ community, mandates that at least one resident in each home is over the age of 55. Typically, this type of housing is geared toward people who are retired or semi-retired. Some age-restricted communities set the age limit to 45 or 50, depending on the location. The law that regulates these communities is called the Housing for Older Persons Act of 1995 (HOPA).

But is excluding homebuyers under the age of 55 legal? According to the Fair Housing Act, age is not a protected class under this federal law. The Federal Housing Act, which was established in 1968, only protects homebuyers and renters from discrimination based on race, color, sex, national origin, religion, familial status, and disability.

But the law does prevent discrimination against familial status, which refers to households with pregnant women or children under the age of 18. Yet HOPA offers exemptions to familial status if the age-restricted community meets certain requirements. In order for the community to qualify, at least one of the following requirements must be followed: all occupants of the community must be over the age of 62 or at least 80% of the occupied homes within the community include at least one resident who is over the age of 55.

Although age-restricted communities are mostly made up of people in the same age group, they may allow underage guests to visit on a temporary basis based on the community rules and limitations. The community associations can determine how long visitors under the age of 18 are allowed to stay as overnight guests or if they need to be accompanied by a resident from the community and be supervised during their stay.

So, what exactly is the appeal to life in a 55+ community? Not a typical subdivision and definitely not a retirement community, active adult neighborhoods offer a built-in community of like-minded residents and many of them offer extensive amenities. Many have a centrally located clubhouse that host hobby rooms, billiards tables, swimming pools, and even golf courses.

Active adult communities are typically located in the usual retirement hotspots like Florida, Arizona, and Texas. But they also have a surprising geographic diversity. Oregon, Michigan, Kansas, and even Alaska all have at least one 55+ community. The state with the most active adult communities outside of Florida? New Jersey, which is the 5th smallest state in the country.

Want to learn more about active adult communities? Head on over to 55places.com to see their list of 100 Most Popular 55+ Communities for 2016.