Ramayana
अपश्यमानस्तं देशं घोरं पुत्रस्य राघव । विन्ध्यशैवलयोर्मध्ये राज्यं प्रादादरिन्दम ॥ 7-79-16 ॥
Not finding any other dreadful region for his son, O Raghava, scorcher of foes, he granted him a kingdom in the area between the Vindhya and the Shaivala mountains.
english translation