GeographyISC Class 12 · Locational Setting

Size, Extent, Coastline and Frontiers of India (ISC Class 12 Geography)

Updated 17 October 2026 · Fact-checked

India covers about 3.287 million sq km, roughly 2.4 per cent of the world's land, and is the seventh largest country. The mainland lies between 8°4'N and 37°6'N and between 68°7'E and 97°25'E. The Tropic of Cancer (23°30'N) cuts it nearly in half, the Standard Meridian is 82°30'E, the coast is about 7,500 km with the islands, and the land frontier of about 15,100 km touches seven countries, the longest being with Bangladesh.

Understand Size, Extent, Coastline and Frontiers of India

1. Size and area. India's area is about 3.287 million sq km (32.87 lakh sq km), about 2.4 per cent of the world's land area. It is the seventh largest country, after Russia, Canada, the USA, China, Brazil and Australia, yet it is the most populous country, so a large share of humanity lives on a small share of the land. The greatest north-south distance is about 3,214 km and the greatest east-west distance is about 2,933 km.

2. Latitudinal extent. The mainland runs from 8°4'N to 37°6'N, a spread of 29°2'. The northern limit used on the map list is Indira Col, and the southern tip of the mainland is Kanniyakumari (Cape Comorin). The southernmost point of the whole country is Indira Point in the Nicobar Islands (about 6°45'N). Because the whole country lies north of the equator, India is in the Northern Hemisphere.

3. Longitudinal extent. The mainland runs from 68°7'E to 97°25'E, a spread of 29°18'. India therefore lies wholly in the Eastern Hemisphere.

4. The Tropic of Cancer (23°30'N). It passes almost through the middle of the country and crosses eight states: Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura and Mizoram. It divides India into a tropical south, which is warm all year with a small range of temperature, and a subtropical north, which has hot summers, cool winters and a larger range.

5. The Standard Meridian and time. The Standard Meridian of India is 82°30'E, near Mirzapur in Uttar Pradesh. Indian Standard Time (IST) is 5 hours 30 minutes ahead of GMT. The earth turns 1° in 4 minutes, so the 29° east-west spread gives a difference of about two hours in local time between the extreme west (Gujarat) and the extreme east (Arunachal Pradesh), although the whole country keeps one time.

6. Coastline. The long-standing official figure is about 7,500 km including the island groups (7,516.6 km), of which about 6,100 km belongs to the mainland. A finer re-measurement adopted in 2024-25 gives about 11,098 km for the same coast, so state which figure you are using. The Arabian Sea lies to the west, the Bay of Bengal to the east and the Indian Ocean to the south.

7. Land frontier. The land frontier is about 15,100 km (15,106.7 km, Ministry of Home Affairs) and India shares it with seven countries: Pakistan, Afghanistan, China, Nepal, Bhutan, Myanmar and Bangladesh. The longest border is with Bangladesh. Sri Lanka is separated from India by the Palk Strait and the Gulf of Mannar, and the Maldives lie to the south-west of the Lakshadweep Islands, so they are maritime neighbours.

8. Natural frontiers. The Himalayas make a lofty barrier in the north, while the sea gives a long open coastline on the other three sides.

Size, Extent, Coastline and Frontiers of India: key facts

Extent in degrees: $L a t i t u d e : 8° 4^{'} N t o 37° 6^{'} N ∣ L o n g i t u d e : 68° 7^{'} E t o 97°2 5^{'} E ∣ S p r e a d = l a r g er v a l u e - s ma l l er v a l u e$
Local time difference: $T im e d i f f er e n ce (min u t es) = d i f f er e n ce in l o n g i t u d e (d e g r ees) x 4∣ E a s t o f 82°3 0^{'} E i s ah e a d o f I S T; w es t i s b e hin d$
Standard time: $I S T = GM T + 5 h 30 min ∣ S t an d a r d M er i d ian 82°3 0^{'} E$
Area facts: About 3.287 million sq km
2.4% of world land
7th largest
N-S about 3,214 km, E-W about 2,933 km
Borders: Coast about 7,500 km (with islands)
Land frontier about 15,100 km
7 neighbours by land

How to answer Size, Extent, Coastline and Frontiers of India questions

For extent and time questions, write the given values, subtract, convert and state the unit.

1Write the two latitudes or longitudes in degrees and minutes.
2Subtract the smaller from the larger, borrowing 60 minutes for 1 degree where needed.
3For time, multiply the longitude difference in degrees by 4 minutes and convert minutes to hours.
4Decide the direction: a place east of 82°30'E is ahead of IST, a place west is behind.
5State the answer with units (degrees, minutes of time, km).

Size, Extent, Coastline and Frontiers of India in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Why one clock for the whole country needs a choice of meridian

Suppose a school in the far east of the country starts classes at 9:00 am IST, while a school in the far west starts at 9:00 am IST on the same morning. A student notices that sunrise comes much earlier in the east.

A town lies at 92°30'E. By how much does its local solar time differ from IST, and is it ahead or behind?

Try it first, then show the solutionSolution

Difference in longitude = 92°30' - 82°30' = 10°.
Time difference = 10 x 4 = 40 minutes.
The town is east of the Standard Meridian, so its local time is ahead.

Answer: Local time is 40 minutes ahead of IST.

Memory hook: East is earlier: add 4 minutes per degree.

Reading an atlas for a border trip

Suppose a student plans an imaginary journey that touches every country that shares a land border with India, starting from the north-west and moving east.

List the seven neighbours in an order that follows the border from west to east, and state which gives the longest border.

Try it first, then show the solutionSolution

Start in the north-west with Pakistan and Afghanistan.
Move along the Himalayan arc: China, Nepal, Bhutan.
Finish in the east with Myanmar and Bangladesh; Bangladesh has the longest border.

Answer: Pakistan, Afghanistan, China, Nepal, Bhutan, Myanmar, Bangladesh; longest border with Bangladesh.

Memory hook: Think of a hand going clockwise along the northern edge.

Tricks to remember Size, Extent, Coastline and Frontiers of India

Short memory aids. Say each one aloud once, then use it on a question the same day.

29 and 29
Both the latitude spread and the longitude spread are about 29 degrees, so India is nearly as wide as it is long.
Use it when: Recalling extent questions.
Tropic crosses eight: G R M C J W T M
Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura, Mizoram, in order from west to east.
Use it when: Listing the states on the Tropic of Cancer.
Four minutes per degree
The earth turns 360 degrees in 24 hours, so 1 degree is 4 minutes. East is ahead, west is behind.
Use it when: Local time and IST questions.

Size, Extent, Coastline and Frontiers of India: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Latitudinal spread · 2 marks · Short answerBoard level

The mainland of India extends from 8°4'N to 37°6'N. Find its latitudinal extent in degrees and minutes.

Try it first, then show the solutionSolution

Subtract: 37°6' - 8°4'.
Degrees: 37 - 8 = 29; minutes: 6 - 4 = 2.
Extent = 29°2'.

Answer: 29°2'.

Example 2: States on the Tropic of Cancer · 2 marks · Short answerBoard level

State the latitude of the Tropic of Cancer and name any four states through which it passes.

Try it first, then show the solutionSolution

The Tropic of Cancer is at 23°30'N.
It crosses Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura and Mizoram; any four earn the mark.

Answer: 23°30'N; for example Gujarat, Rajasthan, Madhya Pradesh and West Bengal.

Example 3: Local time east of the Standard Meridian · 3 marks · Short answerHarder board level

A town lies at 94°30'E. (a) Find the difference between its local time and IST. (b) If IST is 10:00 am, what is the local time of the town?

Try it first, then show the solutionSolution

(a) Longitude difference = 94°30' - 82°30' = 12°.
Time difference = 12 x 4 = 48 minutes; the town is east, so it is ahead.
(b) Local time = 10:00 am + 48 min = 10:48 am.

Answer: (a) 48 minutes ahead of IST (b) 10:48 am.

Example 4: Local time west of the Standard Meridian · 4 marks · Long answerHarder board level

A port lies at 69°30'E. When it is 6:00 pm IST, find the local time at the port. Also state why India does not use two time zones, giving one effect of the single zone.

Try it first, then show the solutionSolution

Longitude difference = 82°30' - 69°30' = 13°.
Time difference = 13 x 4 = 52 minutes; the port is west, so it is behind.
Local time = 6:00 pm - 52 min = 5:08 pm.
One standard time is used because it keeps railway, air and broadcast timetables uniform across the country; the effect is that sunrise and sunset in the far east occur about two hours earlier by the clock than in the far west.

Answer: 5:08 pm local time; one time zone keeps timetables uniform, at the cost of an early sunrise in the east.

Example 5: Two coastline figures · 4 marks · Long answerHOTS / competency

A student writes in an examination that the coastline of India is 7,516.6 km, and another writes 11,098 km. (a) Can both be correct? (b) How should a candidate present the answer? (c) Which part of the figure belongs to the mainland?

Try it first, then show the solutionSolution

(a) Both can be correct as numbers: the first is the long-standing figure and the second comes from a finer re-measurement adopted in 2024-25 for the same coast.
(b) A candidate should state the figure with its basis, for example about 7,500 km including the islands, and may add the newer figure with a note.
(c) About 6,100 km of the older figure belongs to the mainland; the rest is the coastline of the island groups.

Answer: Both are valid by different methods; present about 7,500 km with islands (older) and mention 11,098 km as the newer measurement; mainland share about 6,100 km.

Where students lose marks in Size, Extent, Coastline and Frontiers of India

The slips examiners see most often, and what to write instead.

Mistake: Reversing ahead and behind in time questions
Candidates add time for a place west of the Standard Meridian.
Wrong working
Place at 72°30'E, IST 3:00 pm: 3:00 pm + 40 min = 3:40 pm
Right working
72°30'E is west of 82°30'E, so subtract: 3:00 pm - 40 min = 2:20 pm
Do this: East is ahead, west is behind: add going east, subtract going west.
Usually costs: 1 to 2 marks.
Mistake: Subtracting degrees and minutes incorrectly
Minutes are subtracted as decimals or the borrow of 60 is forgotten.
Wrong working
97°25' - 68°7' = 29°-18'
Right working
97°25' - 68°7' = 29°18'
Do this: Subtract minutes first; if the top minutes are smaller, borrow 1 degree = 60 minutes.
Usually costs: 1 mark.
Mistake: Quoting the coastline without a basis
Two official figures exist, and the answer gives one without saying whether islands are included.
Do this: Write about 7,500 km including the islands and mention the mainland share of about 6,100 km.
Usually costs: 1 mark.
Mistake: Confusing the Standard Meridian with the Tropic of Cancer
One is a line of longitude, the other of latitude.
Do this: 82°30'E is a meridian (time); 23°30'N is a parallel (climate).
Usually costs: 1 mark.

Exam tips

Show the subtraction line and the unit in every extent and time question.
Name the map reference points: Indira Col, Kanniyakumari, 23°30'N and 82°30'E.
List the seven neighbours clearly and state Bangladesh as the longest border.
Keep this page's facts about size separate from the idea of a subcontinent, which is covered under the Indian Ocean location topic.

Practice questions on Size, Extent, Coastline and Frontiers of India

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
The Standard Meridian of India is:
(a) 68°7'E
(b) 82°30'E
(c) 97°25'E
(d) 23°30'E
Hint
It passes near Mirzapur.
Answer
(b) 82°30'E.
Q2 · 2 marks · Short answerHarder board level
Calculate the longitudinal extent of mainland India from 68°7'E to 97°25'E.
Hint
Borrow 60 minutes from a degree if needed.
Answer
97°25' - 68°7' = 29°18'.
Q3 · 3 marks · Short answerHarder board level
A place is at 72°30'E. If IST is 3:00 pm, find its local time and state whether it is ahead of or behind IST.
Hint
Use 4 minutes per degree.
Answer
Difference = 82°30' - 72°30' = 10°, so 40 minutes; the place is west, so it is behind; local time = 2:20 pm.
Q4 · 3 marks · Short answerHarder board level
Explain how the position of the Tropic of Cancer divides India into two climatic zones, and name the two zones.
Hint
Temperature range south and north.
Answer
The tropic passes through the middle of the country. South of it lies the tropical zone with high temperatures all year and a small range; north of it lies the subtropical zone with hot summers, cool winters and a larger range.
Q5 · 1 mark · Assertion-reasonHOTS / competency
Assertion (A): Sri Lanka and the Maldives are not counted among India's land neighbours.
Reason (R): India shares land frontiers with seven countries and is separated from Sri Lanka by the Palk Strait and the Gulf of Mannar.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Hint
Is the sea between them part of the reason?
Answer
(a). Both are true; the sea separation explains why Sri Lanka is a maritime, not a land, neighbour (the Maldives are also across the sea).

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.Area of India and its world rank?Show answer
About 3.287 million sq km; seventh largest.
2.Latitudinal and longitudinal extent of the mainland?Show answer
8°4'N to 37°6'N and 68°7'E to 97°25'E.
3.Number of states crossed by the Tropic of Cancer?Show answer
Eight.
4.Relation between IST and GMT?Show answer
IST = GMT + 5 hours 30 minutes.
5.Which neighbour shares the longest land border with India?Show answer
Bangladesh.

Size, Extent, Coastline and Frontiers of India: frequently asked questions

Why is 82°30'E chosen as the Standard Meridian?

It lies near the middle of the country's east-west spread and passes near Mirzapur, so one time suits the whole country reasonably well.

Which is the southernmost point of India?

Indira Point in the Nicobar Islands for the whole country; Kanniyakumari for the mainland.

How many countries share a land border with India?

Seven: Pakistan, Afghanistan, China, Nepal, Bhutan, Myanmar and Bangladesh.

Why do two coastline lengths appear in books?

One is the older official measurement of about 7,500 km, the other a finer re-measurement of about 11,098 km.