How many years did the triassic last for?

The Triassic period lasted for approximately 51 million years, beginning around 252 million years ago and ending about 201 million years ago. It is the first period of the Mesozoic Era, following the Permian period and preceding the Jurassic period. The Triassic is characterized by the emergence of dinosaurs and the diversification of various life forms after the Permian-Triassic extinction event.