If you said Houston, you'd be wrong.
The fourth largest city in the United States is the US prison system. It holds 2.1 million inmates at any given time, which also makes it the 36th largest state.
I say this, because our, errrrrm, President actually wants to increase the prison population as part of his new immigration scheme.
On enforcement, he pledged to harden the border with increased manpower and new technology including unmanned aerial surveillance. He proposed returning illegals to hometowns in Mexico's interior and adding capacity to detention facilities.It could conceivably vault the US detention system to the third largest city (so long, Chicago).
By contrast, there are 40,000 people in Canadian prisons. Mind you, Canada has the *second* highest rate of incarceration in the developed world! In fact, America holds the dubious distinction of having roughly 25% of the world's prison population (but only 5% of the world's population).
Food for thought.