The United Federation of Planets is a group of people, mainly consisting of humans, that strive towards peace. Humans founded this organization, and it all started in the year 2063, when Zephram Chocrane built the first ship capable of warp travel. This discovery made the Vulcans stop by Earth to take a look.
After a losing war with the Romulans about 100 or so years later, they had to search for new allies.
Around the 23rd Century, the Federation was well established, had some powerful ships, and started to really explore the galaxy. Many new races and things were discovered by the famous captain of the U.S.S.(Untited Star Ship) Enterprise. His name was James Tiberius Kirk.
In the 24th Century Starfleet had grown to be big, consisting of hundreds of different races. Technology was getting better, and more advanced ships were being built. These ships came in use soon, as in the late 24th Century, the Federation and its allies ended up in a good share of wars including several battles with the Borg Collective, the Dominion War, and many devastating skirmishes with the Cardassions, the Son'a, and other races.