Woodstock didn't take place in Woodstock.
The festival of 15 to 18 August 1969 was planned for Woodstock, New York, then for Wallkill, where the town blocked it by law. It moved to Max Yasgur's farm near Bethel, about 100 kilometres away. Instead of the expected 50,000, more than 400,000 people came. Fences and ticket booths were never finished, so the festival became free in practice.
Useful: The name of an event sticks even when the facts have long moved on.
Source: en.wikipedia.org