Street gangs are active in 94% of America's major cities, and they operate in at least 1,130 U.S. cities of all sizes, USC researchers said Monday.
"We were stunned," said co-researcher Malcolm W. Klein, a professor of sociology and director of USC's Center for Research on Crime and Social Control.
Previous estimates, based on surveys far more limited in scope, set the number of U.S. cities experiencing gang activity at about 200, he said.
Klein and another USC researcher, with support from the National Institute of Justice, have spent the past two years surveying gang investigators and law enforcement officials across the country.
Of the nation's 189 cities with populations of 100,000 or more, 177--or 94%--reported gang activity, the USC researchers said. Authorities in more than half of those cities--56%--reported that gang activity in their towns began sometime after 1984.