From PBS and Frontline: With unprecedented access, FRONTLINE investigates the impact of mass incarceration in America, focusing on a troubled housing project in Louisville, Kentucky, and a statewide effort to reverse the trend. There are some 2.3 million people behind bars in the U.S. today, but a disproportionate number come from a few city neighborhoods, and in some places the concentration is so dense that states are spending millions of dollars a year to lock up residents of single blocks. "Prison State" examines one community, Louisville's Beecher Terrace housing project, and follows the lives of four residents as they move in and out of custody, while Kentucky tries break that cycle and shrink its prison state.