According to this data, currently one in every hundred adult citizens of the country is in prisons and colonies. The total number of prisoners in the US is 2.3 million people. For comparison: in China with a population of 1.5 billion, there are people in prison, and in Russia with 145 million - 890,000.
The US leads not only in the number of prisoners, but also in their share of the population, ahead of countries such as Iran and South Africa. In addition, according to this study, the trend of increasing prisoner numbers continues in the US. Thus, from 1987 to 2007, the number of people sentenced to imprisonment tripled.