Cary was curious how many people are in jail for drugs.  Well, let's start with a basic rundown, shall we?

Approximate number of people incarcerated for drug related crimes:

• 108,000 people in federal prisons as of April 2010
• 280,000 people in state prisons across the country as of June 2007
• 31,500 people in California state prisons as of December 2008 

• 211,455 inmates at federal prisons as of April 2010
• 1,395,916 inmates in state prisons as of June 2007
• 171,161 inmates in California as of December 2008

Lots of information is publicly available about almost every aspect of  prisons in the United States, but aggregations seem to take a while to compile.  Really excellent information can be found via the Bureau of Justice Statistics, which is a division within the US Department of Justice. But as they are pulling numbers from a variety of different governmental agencies, their reports come out a few years after the fact. 

It is worth noting that the United States has the highest prison population rate in the world.  In the US, 756 out of every 100,000 people are incarcerated.  

Federal prison system

The federal prison system in the United States is the set of prisons managed by the US Bureau of Prisons, which is an agency of the US Department of Justice. A well-known federal prison is Leavenworth Penitentiary in Kansas. When it was still in operation, Alcatraz was also a federal prison. 

As of the end of April, 2010 there were 211,455 prisoners in the federal system (source), and of those approximately 51.5% are there for drug related offenses (source).  The current numbers are released weekly.  

You would end up in a federal prison for drug-related charges if your crime is committed at the federal level.  One easy to understand example of a drug charge being prosecuted in federal court is when illegal drugs are transported across state lines.  If convicted, sentencing guidelines require mandatory minimum sentences, and there is no ability for a judge to deliver a sentence under that minimum.  These minimum sentences have been in place since the Anti-Drug Abuse Act was passed in 1986.

There is a lot of overlap between federal drug laws and state drug laws.  But there are also areas of contention. There has been a lot of press in recent years about states where medical marijuana has been legalized.  At this time, there is a contradiction between what is legal in that state vs. what is legal federally.  So an individual who is in compliance with all state laws could potentially still be prosecuted for a crime and put in federal prison.  

Back in 2001, it cost on average $22,000 annually per inmate in federal prisons (source).  If it cost the same to incarcerate those individuals now, it would be $2,200,000,000 annually to incarcerate the 100,000 people in federal prison who are there for drug charges.  However, I'd say it's fair to say that this number has likely gone up in the past 9 years. 

State prison systems

State prisons handle most prisoners in the US .  San Quentin in California and Attica in New York are both state prisons.  Prisoners convicted under the laws of an individual state will go to state prisons (unless a sentence is less than a year, in which case they might remain in a city or county jail).

The Bureau of Justice statistics put out a report in June 2008 which addressed the statistics for drug related offenses as of year-end in 2005.  At that time, there were 1,296,700 inmates in state-run correctional facilities, and of those, 253,300 were there for drug related offenses, or around 20% of the incarcerated population nationwide.  The same report indicated that there were 1,395,916 inmates in state-run correctional facilities as of mid-year 2007.   If we assume the percentage for drug related offenses remained similar, then the amount as of June 2007 was likely around 280,000 individuals incarcerated for drug offenses in state prison systems.

California state prison system

The California Department of Corrections and Rehabilitation (CDCR) manages state prisons in California.  I found official statistics for CDCR state prisons as of 2008 in the annual report published in the fall of 2009.  The report is published on the CDCR website. 

As of December 31, 2008, the in-prison population of California was 171,161 people, including 159,753 male inmates and 11,408 female inmates.  At that time, drug offenders comprised 17.8% of the male inmate population and 27.2% of the female population.  That means that 31,529 people were in prison in California for drug offenses at the end of 2008.

In the overview budget report for the CDCR on March 19, 2009, it indicated that the average cost to detain an inmate in California was $48,843 annually (source), which translates to roughly $1.5 billion to incarcerate people for drug crimes annually in California.