Uttara Kuru is the northernmost region of Jambū-dvīpa. It is a land of lasting blessing. Trees bear clothing and jewels of their own accord, the earth is set with gems, and the people live 14,000 years in perfect equality, without disease or old age.

The Mārkaṇḍeya Purāṇa tells of Uttara Kuru as the place where devas are born when the puṇya (merit) they earned in svarga is used up, before they rise again to higher realms. It is also the place where Saṃjñā did her tapas in the form of a mare before she met Sūrya again. The northern stream of the Gaṅgā, called Bhadrasomā, flows to this region.

Description

Uttara Kuru lies at the northern end of Jambū-dvīpa, beyond the Śṛṅgavanta mountains. The Purāṇa describes it in these words:

Trees bear clothing and jewels of their own accord. No farming is needed.
The earth itself is set with gems.
The wind is always pleasant, and the seasons bring no hardship.
The people are born in male-female pairs and die together.
All the people live 14,000 years without old age, disease or bodily decay.
All are equal in looks and in station. No distinctions of class or rank exist there.

Devas who have used up their svarga-puṇya are born again here before they rise once more to higher realms. In this way the region is a bridge between the celestial and the earthly.

(Mārkaṇḍeya Purāṇa, Chapter 56.)

Neighbouring regions of Jambū-dvīpa

The Purāṇa also describes other regions of Jambū-dvīpa that have wonders of their own:

Kimpurusha-varsha. The people live 10,000 years and drink the juice of the plaksha fruit.
Harivarsha. The people are silvery in colour and live 13,000 years. They drink caraka-rasa, a sacred drink.
Ilāvṛta-varsha. It is lit only by the self-shining light of Meru. The people are lotus-like in colour and live 13,000 years. The light of the sun is replaced here by the light of the mountain itself.

(Mārkaṇḍeya Purāṇa, Chapter 56.)

The northern stream of the Gaṅgā

The northern stream of the Gaṅgā, called Bhadrasomā, flows from the summit of Meru straight to Uttara Kuru. She brings the celestial holy waters to this northernmost land, and her waters make even this blessed region holier.

(Mārkaṇḍeya Purāṇa, Chapter 53.)

The tapas of Saṃjñā

Saṃjñā, wife of Sūrya, could no longer bear the great tejas (radiance) of her husband. She chose Uttara Kuru as the place for her tapas. She took the form of a mare and went to these northern lands. She performed hard austerities here.

Viśvakarma had reduced Sūrya’s radiance on the divine lathe. Sūrya then came to Uttara Kuru in the form of a horse and found her there. When they met again in this northern land, the Aśvins were born: Nāsatya and Daśra.

(Mārkaṇḍeya Purāṇa, Chapters 74–75.)

A destination of the widowed queens

In the Āśramavāsika Parva of the Mahābhārata, Vyāsa showed the warriors who were killed at Kurukshetra to their families at the Gaṅgā. After this, the widowed kshatriya queens entered the holy waters at Vyāsa’s word and followed their husbands to their own lokas. Vaiśampāyana records that the places they reached included devaloka, Brahmasadana, Varuṇaloka, Kuberaloka, Yamaloka, the realms of the rākshasas and piśācas, and Uttara Kuru. Uttara Kuru is named last among the many wonderful gatis (destinations) that this company reached.

(Mahābhārata, Āśramavāsika Parva, Chapter 33.)

Sources

Mārkaṇḍeya Mahā Purāṇa, Chapter 53 (the northern stream of the Gaṅgā)
Mārkaṇḍeya Mahā Purāṇa, Chapter 56 (description; neighbouring regions)
Mārkaṇḍeya Mahā Purāṇa, Chapters 74–75 (Saṃjñā’s tapas)
Mahābhārata, Āśramavāsika Parva, Chapter 33