The Shire is the land in the south-west of Middle-earth where Hobbits live--loosely, the land between the River Baranduin (Brandywine) and the Emyn Beraid (Tower Hills). The Shire is a land rich in agriculture, and its people pride themselves on being peaceful, productive, and definitely not in any way adventurous.
Except for those crazy Tooks, Brandybucks, and Bagginses. Oh, those Bagginses.
Gandalf is known to be a particular fan of the Shire's Pipe-weed.
Despite what the Suethors may think, Hobbiton is not the entirety of the Shire, which is also a long, long way from Rivendell.