Ujjālaka (also written Ujjalaka) is a vast sand desert in the maru-deśa (desert country) named in the Vana Parva of the Mahābhārata. It is the place where the great asura Dhundhu, son of Madhu and Kaiṭabha, lay buried in a deep yogic sleep.

Once a year, for seven days in a row, Dhundhu sent out fire and smoke. This yearly blaze made the nearby āśrama of Uttaṅka Maharshi impossible to live in. Ujjālaka was also the place where Kuvalāśva and his twenty-one thousand sons came to dig for Dhundhu and slay him.

Description

Ujjālaka is a vast stretch of sand that spreads over many yojanas (a measure of distance), like an inland sea made wholly of sand. Uttaṅka Maharshi describes it as lying wholly in the maru-deśa, near his āśrama.

Under its sands lay Dhundhu, the son of the first asuras Madhu and Kaiṭabha, sleeping in a deep buried sleep. Once a year, when Dhundhu breathed in and out, the whole region suffered:

The earth shook, and mountains and forests swayed from the shaking.
Fire, smoke and huge clouds of dust burst out of the sand and hid the sun.
The whole area burned for seven days in a row.
The air became impossible to bear.

Because of this yearly event, Uttaṅka’s āśrama, though a beautiful and peaceful place, could not be lived in for one week every year. He could not do his tapas (austerity) without a break. (Mahābhārata, Vana Parva)

The digging of the sands

Kuvalāśva came to Ujjālaka with his twenty-one thousand sons. His father Bṛhadaśva had sent him, and it was also the divine will of Bhagavān Vishṇu. The army began to dig into the sand to reach the body of Dhundhu. An army tunnelling into a vast desert is one of the striking details of the episode.

When they finally broke Dhundhu’s sleep and he woke, fire poured from his body. It burned most of Kuvalāśva’s sons within the sands of Ujjālaka itself. Only three sons lived: Kapilāśva, Dṛḍhāśva and Candrāśva. Kuvalāśva then loosed the Āgneyāstra, the weapon of fire, which destroyed Dhundhu and ended the danger for ever. (Mahābhārata, Vana Parva)

Where it lies

The Mahābhārata does not say more about where Ujjālaka lies than that it is in the maru-deśa near Uttaṅka’s āśrama.

The Vishṇu Dharmottara Purāṇa tells the same account (Pūrvārdha, Chapters 15–16). It calls Dhundhu a jala-rākshasa (a rākshasa of the water) who lived beneath an inland sea of sand.

Sources

Mahābhārata, Vana Parva, Chapters 201–204
Vishṇu Dharmottara Purāṇa, Pūrvārdha, Chapters 15–16