Following the start of the war on drugs in the 1970s, America's prison population skyrocketed as the country locked up even the lowest-level drug offenders in hopes of tamping down on drug use and the crime wave of the 1960s through 1980s.

This map, from Twitter and Reddit user MetricMaps, shows just how quickly the nation's prison population exploded from state to state:

While incarceration can help bring down crime to some degree, criminal justice experts generally agree US imprisonment has become an ineffective deterrent to crime as it's extended far beyond the point of diminishing returns. Federal and state data shows there is no correlation between decreases in the prison population and rises in crime. And an analysis by the Pew Public Safety Performance Project found the 10 states that shrunk incarceration rates the most over the past five years saw bigger drops in crime than the 10 states where incarceration rates most grew.

Federal and state officials have attempted to reverse the mass incarceration trend in recent years through reforms that reduced sentences on certain crimes, particularly nonviolent drug offenses, and allow low-level offenders to get out of prison earlier under special circumstances.

So far, there has been a small reversal. The overall imprisonment rate dropped, particularly in California, in the past few years. And the US corrections population — the number of people in jail, prison, parole, and probation — in 2013 dropped to its lowest point since 2003, according to a report from the Bureau of Justice Statistics.

But the reversal hasn't been enough to keep up with the rapid decline of violent crime across the country. Federal statistics show that the incarceration rate fell by roughly 1 percent between 2000 and 2013, even as violent crime fell by about 27 percent in the same time period.

Experts argue more aggressive reforms will be needed in the next few years to ensure the incarceration rate continues its downward trend. "We didn't get to today's incarceration rate overnight," said Brian Elderbroom, senior research associate at the Urban Institute's Justice Policy Center. "We're not going to get to the imprisonment rates that we believe are more appropriate overnight."

Read more: Why 2014 could be a turning point for America's racist criminal justice system.