The US prison population has risen further, with one in 138 people now in jail, new official figures reveal.
The prison population has risen this year, the report says
There are more than 2.1 million US citizens in jail - more than in any other country, the Bureau of Justice Statistics says.
The government says putting and keeping criminals in jail is working. Recent figures have shown violent crime and murder falling.
But critics say less severe ways of approaching crime are being ignored.
The figures show the prison population increased by an estimated 48,452 people - 2.3% - in the year to 30 June 2004.
US: 726 people per 100,000
Source: Justice Policy Institute
It means the incarceration rate reached a record of 726 people per 100,000 residents.
The Justice Policy Institute, which advocates alternatives to prison, says it is the highest rate in the world - more than five times that in Britain, and 12 times that in Japan.
The prison population is swelling fastest in the state of Minnesota - up 13.2% over 12 months.
People from some social groups in the US are far more likely to end up in prison.
The figures showed that 12.6% of black males in their late 20s are in prison, compared to 3.6% of Hispanics and about 1.7% of whites.
The continued rise in imprisonment was due to tough policies brought in to tackle high crime rates over the last 20 years, said Paige Harrison, a justice department official who co-wrote the report.
"As a whole most of these policies remain in place," she said.
But Malcolm Young, of the Sentencing Project, which promotes other forms of punishment, said many of those languishing in prison were not dangerous, but low-level drug offenders.
Some critics have said putting lesser offenders in prison with hardened criminals increases the likelihood that they will re-offend on release.
Jason Ziedenberg, of the Justice Policy Institute, said: "Unless we promote alternatives to prison, the nation will continue to lead the world in imprisonment."