Picture a facility many of whose occupants are obviously frail, ill or disabled. Most have sparse or graying hair. A number lean upon canes or walkers; others navigate by means of wheelchairs. Some cannot even leave their beds or eat and drink without assistance. Surely this must be a senior citizens’ or nursing home. But if so, why are the denizens all male and dressed in identical colored jumpsuits? The answer is that you are looking at a prison — and not a unique one.

According to two recent reports by the American Civil Liberties Union and Human Rights Watch, the population of elderly inmates has risen dramatically since 1980. ACLU, At America’s Expense: The Mass Incarceration of the Elderly; Human Rights Watch, Old Behind Bars: The Aging Prison Population in the United States. Currently almost 250,000 prisoners, about 16 percent of imprisoned convicts, are above 50; they can be considered “old.” (Given the lack of decent health care before and after incarceration as well as the stresses of life in prison, their greater physiological age makes 50 an appropriate marker.) By 2030, experts predict, the proportion 55 and older will grow to one-third — an escalation since 1981 of 4,400 percent.