On a sunny afternoon in May, about a dozen inmates at Otisville prison camp played handball. Adjacent to the court was a low-slung, drably painted housing unit. No perimeter fence or barbed wire surrounded the grounds, located roughly two miles up a winding road through dense, rocky forest. Canada geese waddled nearby as the inmates — clad in regulation shorts and T-shirts and shaved heads — worked up a sweat.

But for a lone guard, it would have been easy to overlook the fact that the players happened to be prisoners.

For federal inmates, this is about as good as it gets. The Federal Correctional Institution in Otisville, roughly 80 miles north of New York City, is one of several dozen minimum-security prisons — typically called camps — in the federal Bureau of Prisons system, where many white-collar convicts end up serving out their sentences. Unlike the low-, medium-, and high-security institutions where most inmates do time, camps are not fenced in. The doors aren’t even locked.