Based on formal tallies, the U.S.'s prison population is the highest of any country in the world including China, both in terms of per capita prisoners and total number of prisoners.
The U.S.'s incarceration rate was 639 per 100,000 in 2021, according to World Population Review. China's ranks 116th with 121 per 100,000.
Despite having less than a quarter of China's population, the U.S. also has the highest overall prison population at more than two million. China's is approximately 1.7 million. Globally, the U.S. accounts for 4% of the population and 25% of prisoners.
China's figure does not include detainees located in Xinjiang internment camps, which are reportedly used to indoctrinate Uyghurs and other Muslims. While China has not provided numbers, a recent estimate based on satellite images, public spending on detention facilities, and witness accounts of overcrowded facilities and missing family members placed the number of detainees at 1.5 million.