People over the age of 65 in a given area (such as the counties of Pennsylvania) traditionally represents those who are retired or are considered elderly. The number of these individuals in a county is affected by local life expectancy factors as well as by genetics. While many who reach this age will act on their wealth and lifestyle preferences by moving to warmer climates, the majority prefer to stay in familiar surroundings and in the homes they have worked to acquire and maintain throughout their working years. It is also important to note that modern medicine and other resources are allowing older Americans to live (and even work) longer and stay healthier than previous generations.

The percentage of the population in this age category is affected by these factors as well as by the decisions of younger people to leave or stay in the county. An increasing percentage of population 65 and over will require an increasing percentage of products and services tailored to older Pennsylvanians.

The map comparison between these three time periods, as well as the table below, show how dramatically Pennsylvania's population is aging. The maps also show that most of those counties requiring these adjustments are located in northern and western Pennsylvania.