From "Everything A Hacker Needs To Know About Getting Busted By The Feds" (just Google it)

"The lowest level facility is called a minimum, a camp, or FPC. Generally speaking, you will find first time, non-violent offenders with less than 10 year sentences there. Camps have no fences. Your work assignment at a camp is usually off the prison grounds at a nearby military base. Other times camps operate as support for other nearby prisons."

from wired.com news:
"He [McKinnon] faces anywhere from six months to six-and-a-half years in prison under federal sentencing guidelines, depending on how much damage he caused, if any, and whether or not he accepts responsibility."

It is not 70 or 80 years as some UK media have reported.