sinetific is right, in the US you can be "held" in jail, usually pending trail, and sometimes for several weeks. To put it a different way, sometimes the "holding tank" is simply the jail. Soooo, yes, you can be "jailed" for misdemeanors, felonies, traffic tickets, and now even peaceful protests in some places.
Prison is another story, and *I think* it is reserved for felons. When I was arrested in Ohio the jail was a 20-person dorm-style room. Most prisons have 1-2 person cells with bars.
One more thing... this is what really pisses me off about the justice system here. ohfuk's story is very typical, police had reason to arrest (and imprison) him, even as a juvenile, yet they did not. This is non-enforcement of the law, like they used to do with inet piracy. This leads everyone to think "well, it's OK, no one is getting arrested for it" and it becomes socially acceptable. Then, when it becomes politically convenient, or when the cops need to fill their quota, they decide to enforce it.
What do you do? ...
Back off, man! I'm a scientist... - Peter VenkMann