Incarceration rates don't necessarily correlate with corruption, but they do reflect the extent to which a given nation's government is (by means of its laws and its enforcement of those laws) at war against its own population; and, so, technically speaking, it's supposed to reflect the prevalence of law-breaking within that nation. After all, by definition, people are presumed to be in prison for law-breaking, irrespective of whether the given nation's laws are just - and, if they're not just, then this fact reflects even more strongly that the nation itself is corrupt. So, a high incarceration-rate does strongly tend to go along with a nation's being highly corrupt, in more than merely a technical sense.
Out of the world's 223 countries, the US has the world's second-highest incarceration rate: 698 per 100,000, just behind #1 Seychelles, with 799 per 100,000. Seychelles doesn't even have as many as 100,000 people (but only
90,024 - as many people as are in the city of Temple Texas). By contrast, the US has
322,369,319; so, the US is surely the global leader in imprisonment. And, furthermore, #3, St. Kitts and Nevis, with an incarceration-rate of 607 per 100,000, has only
54,961 people (as many people as are in the city of Columbus Indiana). The only other country that might actually be close to the US in imprisoning its own people is North Korea, which could even beat out the US there, but wouldn't likely beat tiny Seychelles: North Korea is
estimated to have "600-800 people incarcerated per 100,000", and a total population of 24,895,000.
Comment: More information: