When did old faithful last erupt?

Answer 1

Old Faithful was created by a hot spot.

Old Faithful is the world's most famous geyser. Situated in yellowstone-national-parks Upper Geyser Basin, it was given its name by members of the washburn, langford, doane expedition because of its predictable eruptions, every 60-90 minutes. Each eruption lasts 1.5-5 minutes, expelling some 3,700-8,400 gallons of boiling water (14,000-32,000 liters) in a narrow jet stream.

Old Faithful facts:

• Each eruption lasts one and a half to five minutes.
• When it erupts, it sprays 3,700 to 8,400 gallons (14,000 to 32,000 liters) of boiling water up to 184 feet (55 m) in the air.
• Old Faithful has rarely missed an eruption in over 120 years of recorded history
• Old Faithful is one of more than 300 geysers in Yellowstone.
• Old Faithful is a cone geyser, named for the cone-shaped mineral formation around its opening that makes it erupt in a narrow jet.
  

Answer 2

It is nearly impossible to accurately gauge the exact age of a geyser due to extensive variables in its formation and lifespan, but based on its most recent eruption, scientists believe the geyser is less than 150,000 years old.