The original Star Trek series was released two decades before Star Trek: The Next Generation, but how many years separated the two shows in the universe? Star Trek: The Next Generation had big shoes to fill when it premiered in 1987 and jump-started the Star Trek TV franchise years after the cancelation of The Original Series. It presented an entirely different view of the Star Trek universe, and it was clear that a lot had changed since Captain Kirk commanded the USS Enterprise.
Star Trek's entire timeline was documented with precision by writers, and nearly every important moment was assigned a specific point in the history of the future. As such, the intervening years between Star Trek: The Original Series and Star Trek: The Next Generation were quite specific, and that strong sense of continuity was one of the most important aspects of the franchise as a whole. The adventures of Captain Jean-Luc Picard and the rest of the crew of the Enterprise-D were products of their own time within the Star Trek universe, just like Kirk and Spock's were before them.
Star Trek: The Next Generation Takes Place 95 Years After The Original Series
Though Captain Kirk and his crew's adventures continued into the 2290s during the Star Trek film series, The Original Series actually concluded during the in-universe year of 2269. The conclusion of Captain Kirk's first five-year mission wasn't shown in the short-lived original program, but the year was firmly established within the canon nevertheless.
Star Trek: The Next Generation began in the year 2264 during the events of season 1, episode 1, "Encounter at Farpoint," which made it exactly 95 years after Captain Kirk's original mission concluded. Ironically, Star Trek: The Next Generation was technically several generations after Star Trek: The Original Series since generations are generally considered to be every 20 to 30 years.
TOS & TNG Are Still Connected
Despite the fact that a century separated the two series, there was quite a bit of overlap between their characters and storytelling. Several characters from Star Trek: The Original Series, such as Spock and Dr. McCoy, appeared in the later show, and events from the Star Trek: The Original Series era continued to have an impact during Star Trek: The Next Generation.
While some TNG episodes were based on TOS stories, key details like the Khitomer Accords played an important part in the Star Trek: The Next Generation era but actually took place during Star Trek: The Original Series' time. The legacy of the USS Enterprise from Kirk's era still cast its shadow in the 2260s, just as Picard's did further in the future of Star Trek.