Pork Butt is a very unfortunate term, that really ought to be discarded and replaced, as most consumers are never going to really understand it.
It has nothing to do with hind end of the pig. It is in fact a joint of pork from the upper part of the pig's shoulder.
Of the two cuts from the pig's shoulder Pork Butt and picnic cut, Pork Butt is considered the better one. The Butt cut is more tender than the picnic, and most of the bone ends up in the picnic cut.
A Pork Butt will weigh between 6 to 9 pounds (2 3/4 to 4 kg.)
It can be left to be sold as a whole, or it may be cut into slices and sold as pork steaks.
This Pork Butt contains sinew (connective tissue) that needs low, slow cooking to break it down. But, as it breaks down, it leaves a lot of flavour behind.
It can be braised on top the stove or in the oven; it can be barbequed; it can also be stewed.
You can roast it on its own, if you do it very low and slow. It has enough fat to baste itself while roasting.
It is good for pulled pork, and is particularly good on the barbeque.