Key facts

  • Rajasthan covers 3,42,239 sq km (10.41% of India's land area), the largest state in India by area.
  • Four physiographic divisions: Western Sandy Plain (61.11%), Aravalli Range (9.3%), Eastern Plains (23.0%), South-Eastern Plateau/Hadoti (6.6%).
  • Aravalli Range — world's oldest fold mountains (Pre-Cambrian era, ~2,500 million years old), extends 692 km within Rajasthan;
  • Thar Desert (थार मरुस्थल) covers ~61% of Rajasthan's area; average annual rainfall below 25 cm; sand dunes (धोरे) most characteristic landform.
  • Luni (लूनी) — longest river in western Rajasthan (495 km), originates near Pushkar (Ajmer), drains into Rann of Kutch;

Key Points at a Glance

  1. 1

    Rajasthan covers 3,42,239 sq km (10.41% of India's land area), the largest state in India by area.

  2. 2

    Four physiographic divisions: Western Sandy Plain (61.11%), Aravalli Range (9.3%), Eastern Plains (23.0%), South-Eastern Plateau/Hadoti (6.6%).

  3. 3

    Aravalli Range — world's oldest fold mountains (Pre-Cambrian era, ~2,500 million years old), extends 692 km within Rajasthan; highest peak Guru Shikhar (1,722 m), Mount Abu (Sirohi).

  4. 4

    Thar Desert (थार मरुस्थल) covers ~61% of Rajasthan's area; average annual rainfall below 25 cm; sand dunes (धोरे) most characteristic landform.

  5. 5

    Luni (लूनी) — longest river in western Rajasthan (495 km), originates near Pushkar (Ajmer), drains into Rann of Kutch; called "Salt River" as its water turns brackish below Balotra.

  6. 6

    Chambal (चंबल) — longest river flowing through Rajasthan (966 km total), originates in Janapav Hill (MP); the only perennial river with ravine badlands (बीहड़) in Kota-Sawai Madhopur belt.

  7. 7

    Banas (बनास) — longest river entirely within Rajasthan (480 km), originates from Khamnor hills (Rajsamand), meets Chambal at Rameshwar Ghat (Sawai Madhopur).

  8. 8

    Inland drainage (आंतरिक प्रवाह) covers ~60% of Rajasthan — rivers like Ghaggar, Kakni (Luni's tributary), Kantli, and Saraswati (dry) lose water to sand before reaching sea.

  9. 9

    Sambhar Lake (साम्भर झील) — India's largest inland saltwater lake (240 sq km); Ramsar site; produces ~2.5 lakh tonnes of salt annually; Jaipur–Nagaur–Ajmer tri-junction.

  10. 10

    Jaisamand Lake (जयसमंद झील) — historically Asia's second-largest artificial lake; built 1685-91 by Maharana Jai Singh; area ~87 sq km; Udaipur district.

  11. 11

    Indira Gandhi Nahar Pariyojana (IGNP) — 649 km main canal from Harike (Punjab) barrage; world's largest canal irrigation project; transforms Thar Desert; Stage I (204 km) and Stage II (445 km).

  12. 12

    Chambal Valley Development Project — three dams: Gandhi Sagar (MP), Rana Pratap Sagar (Rawatbhata, Chittorgarh), Jawahar Sagar; total installed capacity ~386 MW.

  13. 13

    The Aravalli acts as the main watershed divide: rivers west of it drain into the Arabian Sea (or inland), rivers east drain into the Bay of Bengal via the Ganga-Yamuna system.

  14. 14

    Pushkar Lake (पुष्कर झील) — only lake in India associated with Lord Brahma; freshwater; Ajmer district; unique sacred geography.

  15. 15

    Nakki Lake (नक्की झील) — highest altitude lake in Rajasthan (~1,200 m); Mount Abu, Sirohi; reportedly carved by fingernails (नख) of gods in Hindu mythology. / नक्की झील — राजस्थान की सबसे ऊँची झील (~1,200 मीटर); माउंट आबू, सिरोही।

What does the RPSC syllabus expect you to know about Rajasthan physiography, rivers and lakes?

The RPSC syllabus expects this topic to be studied as one connected geography block: Rajasthan's physical features, major physiographic regions, river systems and lakes.

In the official RPSC Mains syllabus, Paper II is a 200-mark paper, and Unit III, Part C under Earth Science lists Rajasthan's "Broad Physical Features: Mountains, Plateaus, Plains, Rivers and Lakes." That syllabus placement matters because the examiner can combine landforms, drainage and water bodies in the same answer rather than testing them as isolated lists.

The working scope for this note therefore covers three interconnected sub-topics: the four physiographic divisions of Rajasthan, the river systems and their drainage basins, and the major lakes, both natural and artificial. All three must be read together because RPSC frequently frames questions across sub-topic boundaries. A standard example is the role of the Aravalli Range as a watershed between the western, inland and eastern drainage systems.

The PYQ Tier 3 classification, recorded as 4/5 exams with an average of 2.8 marks, indicates consistent but not dominant testing. RPSC usually asks a 5-mark factual question rather than a full 10-mark analytical question. However, the revised 2026 syllabus mapping gives more weight to geographic data, so a 10-mark question on physiography, drainage or lake conservation is more likely than in earlier cycles.

Students who know only the names of rivers and lakes usually score 3-4 out of 5. Students who know lengths, tributaries, basin divisions, dam specifics, lake dimensions, ecological status and location logic can write a full-scoring 5-mark answer and can also stretch the material into a strong 10-mark response.

Adjacent topics provide essential context. Topic #84 on climate explains why western Rajasthan rivers are seasonal. Topic #85 on vegetation connects physiography to watershed ecology. Topic #86 on soils links the river plains with alluvial deposits and red-yellow soils. Topic #88 on minerals explains the geological base of the Aravalli landforms and why that belt hosts metallic and non-metallic mineral deposits.

This chapter covers the four physiographic regions with their area percentages and landform types; the full river classification by drainage basin, including Arabian Sea, Bay of Bengal and inland drainage; key rivers with origins, lengths, tributaries and associated projects; and major lakes with location, dimensions, history, ecological status and exam relevance.

PREDICTED Predicted RAS Questions

Based on PYQ trends and 2026 syllabus analysis

1 5M Name the three drainage divisions of Rajasthan and give one major river system in each. 5 marks · 50 words

Model Answer

Rajasthan has three drainage divisions: (1) Bay of Bengal drainage — Chambal-Banas system (eastern Rajasthan); (2) Arabian Sea drainage — Luni river system (southwestern Rajasthan); (3) Inland drainage — Ghaggar and Kantli rivers (northern Rajasthan, terminating in Thar Desert sands). The Aravalli Range acts as the primary watershed separating these systems.

~50 words • 5 marks