Bg 8.21

avyakto ’ksara ity uktas
tam ahuh paramam gatim
yam prapya na nivartante
tad dhama paramam mama

Word for word: 
avyaktah — unmanifested; aksarah — infallible; iti — thus; uktah — is said; tam — that; ahuh — is known; paramam — the ultimate; gatim — destination; yam — which; prapya — gaining; na — never; nivartante — come back; tat — that; dhama — abode; paramam — supreme; mama — My.

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
That which the Vedantists describe as unmanifest and infallible, that which is known as the supreme destination, that place from which, having attained it, one never returns – that is My supreme abode.

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The supreme abode of the Personality of Godhead, Krishna, is described in the Brahma-samhita as cintamani-dhama, a place where all desires are fulfilled. The supreme abode of Lord Krishna, known as Goloka Vrndavana, is full of palaces made of touchstone. There are also trees, called “desire trees,” that supply any type of eatable upon demand, and there are cows, known as surabhi cows, which supply a limitless supply of milk. In this abode, the Lord is served by hundreds of thousands of goddesses of fortune (Laksmis), and He is called Govinda, the primal Lord and the cause of all causes. The Lord is accustomed to blow His flute (venum kvanantam). His transcendental form is the most attractive in all the worlds – His eyes are like lotus petals, and the color of His body is like the color of clouds. He is so attractive that His beauty excels that of thousands of Cupids. He wears saffron cloth, a garland around His neck and a peacock feather in His hair. In the Bhagavad-gita Lord Krishna gives only a small hint of His personal abode, Goloka Vrndavana, which is the supermost planet in the spiritual kingdom. A vivid description is given in the Brahma-samhita. Vedic literatures (Katha Upanisad 1.3.11) state that there is nothing superior to the abode of the Supreme Godhead, and that that abode is the ultimate destination (purusan na param kiñcit sa kastha parama gatih). When one attains to it, he never returns to the material world. Krishna’s supreme abode and Krishna Himself are nondifferent, being of the same quality. On this earth, Vrndavana, ninety miles southeast of Delhi, is a replica of that supreme Goloka Vrndavana located in the spiritual sky. When Krishna descended on this earth, He sported on that particular tract of land known as Vrndavana, comprising about 168 square miles in the district of Mathura, India.