Mass incarceration is an umbrella term for the phenomena that have contributed to the steep rise in the American prison and jail population in the late-twentieth and early twenty-first centuries.
At present, the population of incarcerated—i.e. sentenced and imprisoned or jailed while awaiting trial—people in the United States is 2.3 million, a figure seven times higher than it was in 1970. This means that the rate of imprisonment has risen faster than crime rates. Consequently, of all the imprisoned people in the world, the United States claims twenty-five percent, despite only having five percent of the global population.
The dramatic rise in incarceration rates is in part accounted for by the increased imprisonment of women, a demographic whose incarcerated population is the country's fastest-growing, rising since the 1980s at a rate 50 percent higher than men’s.
Life sentences also reached a record high in 2017, with 206,000 people serving life in prison, amounting to one out of every seven people in prison. Additionally, two-thirds of the people serving life sentences are people of color.
Though the nationwide prison population in 2017 had declined by 7.3 percent since it reached its highest level in 2009, the decrease has not been even across the country. The fall in incarceration rates is thought to be due to sentencing reforms in the states of Alaska, Connecticut, California, New Jersey, New York, and Vermont.
