CC Madhya 21.91
ei tina loke kṛṣṇera sahaje nitya-sthiti
“The three lokas are Gokula (Goloka), Mathurā and Dvārakā. Kṛṣṇa lives eternally in these three places.
Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura comments that in the Goloka planet there are three divisions: Gokula, Mathurā and Dvārakā. In His incarnation as Gaurasundara, Lord Śrī Caitanya Mahāprabhu, the Lord conducts His pastimes in three areas: Navadvīpa, Jagannātha Purī (and South India) and Vraja-maṇḍala (the area of Vṛndāvana-dhāma).