Chashtana (Greek: Ϲιαϲτανϲας Siastansas (epigraphic),[2] Τιαστανης Tiastanēs;[5] Brahmi: Ca-ṣṭa-na Caṣṭana; Kharosthi: 𐨖𐨛𐨞 Cha-ṭha-ṇa, Chaṭhaṇa[6]) was a ruler of the Saka Western Satraps in northwestern India during 78-130 CE, when he was the satrap of Ujjain.

[9] Among modern scholars, the beginning of the Saka era is widely equated to the ascension of Chashtana (possibly to Mahakshatrapa) in 78 CE.

[4] Chashtana is called Tisman by the bards, a spelling that matches the Greek rendition of his name more closely.

[11] Ptolemy in his "Geographia", where he classifies the Western Satraps as "Indo-Scythians", describes Chashtana's territory as starting from Patalene in the West, to his capital Ujjain in the east ("Ozena-Regia Tiastani", "Ozene, capital of king Chashtana"), and beyond Barigaza in the south: Moreover the region which is next to the western part of India, is called Indoscythia.

(...) The Larica region of Indoscythia is located eastward from the swamp near the sea, in which on the west of the Namadus river is the interior city of Barygaza emporium.