The Picts inhabited Caledonia (Scotland), north of the River Forth. We owe their name to the Romans: in Latin the word Picti means painted folk or possibly tattooed ones. The Picts spoke a language, Pictish, of which little is known.
Modern scholars believe that seven ancient Pictish Kingdoms existed:
From the 6th century AD onwards the Picts came under increasing pressure from the invasions of the Dalriadan Scots in the west and of the Vikings in the east. They defeated Dalriada militarily but intermarried repeatedly with the royal house of Dalriada until in 843 AD Kenneth Mac Alpin took the throne of a united kingdom of Scotland. Gaelic culture and Scots Gaelic gradually supplanted Pictish culture and the Pictish language.
You can often tell where Pictish settlement has taken place in the past (in Scotland) from place names. Those prefixed with "Aber-", "Lhan-", "Pit-" or "Fin-" indicate the region was inhabited by Picts in the past (eg: Aberdeen, Lhanbryde, Pitmedden, Pittodrie, Findochty, etc).