The Picts were the inhabitants of Caledonia
?, north of the River Forth. They spoke a language, Pictish, of which little is known. The ancient Pictish Kingdoms were Ross
?, Fife
? and others.
You can often tell where pictish settlement has taken place in the past from place names. Those prefixed with "pit-" indicate the region was inhabited by Picts in the past (eg: Pitmedden, Pittoddrie, etc)