The Smoke is an established camp in the wilderness, where runaways from cities gathered to avoid the lesions included in the pretty operation.
The Old Smoke
The Old Smoke was established by Maddy and Az (David's parents) in a remote location in the wilderness near railroad tracks. Maddy and Az created it because they found out a secret about the operation. The Old Smoke was destroyed at the end of the first book Uglies, by Special Circumstances. Tally Youngblood accidentally alerted Special Circumstances when she threw her tracker pendant into a fire, as a show of trust and caring for David and The Smoke.
The New Smoke
The New Smoke was thought to be a new camp in the wilderness, but the Smokies formed a partnership with the city of Diego and settled there.