The planet Ba'ku was a M-class planet located in the Briar Patch, in Sector 441. It was the location of a Ba'ku colony, and was characterized by a unique effect caused by the planet's rings that cause the planet's inhabitants not to age.
Ba'ku was a ringed planet, the rings themselves being saturated with metaphasic radiation. The planet was home to a Ba'ku settlement, established in 2066 by a group of approximately 600 of the Ba'ku, fleeing their homeworld for fear of their race's self-destruction. The planet's radiation allowed the inhabitants to live extended life spans, In the late 23rd century, a group of the Ba'ku, disillusioned with the settlement's ways, left the planet, and became the Son'a.
In 2375, an attempt by the Son'a – led by Ahdar Ru'afo, and assisted by Starfleet officers under Matthew Dougherty – to strip the planet of its metaphasic particles and to forcefully relocate the Ba'ku to another planet, was stopped by the actions of Jean-Luc Picard and the crew of the USS Enterprise-E.
There are many species of animal life on the Ba'ku planet, several of which can be seen in a Ba'ku children's book. These species' names are unknown, but pictures have been seen of a six-legged turtle-like animal, a polar bear-like animal, an animal that resembles an ancient Earth pterodactyl, and a Ba'ku butterfly.
According to the Star Trek: Star Charts (p. 60) and on the chart "United Federation of Planets I", Ba'ku was located in the Ba'ku system. This system was located in the Beta Quadrant. This system was a single star system. Primary was a Class K star with a magnitude of +5, which was the same brightness as Sol. Ba'ku was listed as a member planet of the Federation in 2378.