3 years, from 1966 to 1969.
If you mean "Trek History" (not real life) the "Star Trek Enterprise" series gave its first stardate as 2151 and "Star Trek (The Original Series) gave its stardate as 2265 - so about 100 years. (Timelines from Trek Encyclopedia). In real history, Star Trek (TOS) ran from 1966 - 1969 and Star Trek Enterprise ran from 2001 - 2005.
Star Trek: The Original Series Star Trek: The Animated Series Star Trek: The Next Generation Star Trek: Deep Space Nine Star Trek: Voyager Star Trek: Enterprise Star Trek: Bridge Commander (TV Series)
7 Star Trek The Original Series Star Trek The Animated Series Star Trek The Next Generation Star Trek Deep Space Nine Star Trek Voyager Star Trek Enterprise Star Trek Bridge Commander (TV Series)
Only eight were made in a box set of the original Star Trek crew and the U.S.S. Enterprise A
As of 2013, the original Star Trek series is shown on MeTV. This is secondary channel in many parts of the country.
Star Trek (the original series) premiered on September 8, 1966.(Note: The first pilot episode, "The Cage", was completed between November 1964 and January 1965, however, it did not air on TV for the first time as a standalone episode until October 4, 1988.)
three years NBC tried to cancel the show after two years, but so many people wrote to NBC in support of the show that they made one more year of it.
1000-90000
In Star Trek The Original Series Kirk appears in 79 episodes.
Star Trek TOS (The Original Series) has 80 episodes in all. I was jut watching South Park when the subject came up they had it at 72. I know for a fact that it is 79 original episodes of Star Trek over a stretch of 3 seasons :-)
Many people think "Spock's Brain" was the worst.
There were 7 seasons of Star Trek The Next Generation.There were 7 seasons of Star Trek The Next Generation.There were 7 seasons of Star Trek The Next Generation.There were 7 seasons of Star Trek The Next Generation.There were 7 seasons of Star Trek The Next Generation.There were 7 seasons of Star Trek The Next Generation.There were 7 seasons of Star Trek The Next Generation.There were 7 seasons of Star Trek The Next Generation.There were 7 seasons of Star Trek The Next Generation.There were 7 seasons of Star Trek The Next Generation.There were 7 seasons of Star Trek The Next Generation.