Wikipedia
Goloka Dham (Goloka Vrindavana or Gokula) is the supreme loka which is the king of all loka and is the eternal Supreme Abode of goddess Radha rani according to Vaishnava schools, including Gaudiya Vaishnavism and the Swaminarayan Sampraday. The scriptural basis for this comes from texts like Narada Pancaratra, Garga Samhita, Brahma Samhita and Brahma vaivarta. Among all 18 puranas, Brahma vaivarta purana explicitly describes about Goloka vrindavan throughout its all contents.
While in most of the Bhagavata Purana, Krishna is presented as the cosmic Vishnu, the Supremely Powerful God. He is especially portrayed as the highest person who resides in his abode Goloka according to the interpretation of Jiva Goswami.
In the Bhagavata Purana, Krishna states that he shall ascend to his eternal supreme abode, Vaikuṇṭha, after the purpose of his incarnation is accomplished.
According to some sources, Goloka is part of Vaikuṇṭha, while other sources claim that Goloka is a highest planet or realm (loka) of the Vaikuṇṭha planets for the devotees of Krishna, who is known as the protector of cows; hence, the latter are found in abundance in Goloka. Also sometimes referred to as Vrindavan, it is described as a land of plenty, rich with natural beauty.
One standard Vaishnava description of Goloka is found at verse 5.29 of the Brahma-Samhita: "I worship Govinda, the primeval Lord, the first progenitor, who is tending the cows, yielding all desires, in abodes built with spiritual gems and surrounded by millions of purpose trees. He is always served with great reverence and affection by hundreds and thousands of devotees resembling goddesses of fortune." Similarly, Gaudiya Vaishnava saint-scholar Śrĩla Sanãtana Goswãmĩ declares: "Sri Goloka is considered the ultimate destination of spiritual endeavour."
In Goloka Krishna resides with Radharani, Krishna's eternal consort, and countless other devotees, wherein he performs his divine play, known as lila. It is believed that mortal or "conditoned" souls return to the material world again and again to perfect themselves before going on to Krishna's abode, known as the Vaikunthas. However, Goloka Vrndavana is the topmost of all the planets in either the material or spiritual worlds, and rare is the soul who is allowed to go there.
According to Hindu scriptures, the term Goloka is synonymous with Vaikuntha and Saket Loka.