China, population: 1.3 billion+
US, population: 301,439,000
According to the International Centre for Prison Studies at King’s College London, the U.S. currently has the largest documented prison population in the world, both in absolute and proportional terms. We’ve got roughly 2.03 million people behind bars, or 701 per 100,000 population. China has the second-largest number of prisoners (1.51 million, for a rate of 117 per 100,000), and Russia has the second-highest rate (606 per 100,000, for a total of 865,000). Russia had the highest rate for years, but has released hundreds of thousands of prisoners since 1998; meanwhile the U.S. prison population has grown by even more. Rounding out the top ten, with rates from 554 to 437, are Belarus, Bermuda (UK), Kazakhstan, the Virgin Islands (U.S.), the Cayman Islands (UK), Turkmenistan, Belize, and Suriname, which you’ll have to agree puts America in interesting company. South Africa, a longtime star performer on the list, has dropped to 15th place (402) since the dismantling of apartheid.
The Straight Dope, Does the United States lead the world in prison population?, 06-Feb-2004