With which neighbouring country does India share its longest international land boundary?

Introduction / Context:
India shares land boundaries with several countries, and the length of these borders is a common topic in geography and general knowledge exams. Knowing which country has the longest land boundary with India helps learners understand regional geography and strategic relations in South Asia.

Given Data / Assumptions:

• India shares borders with Nepal, Pakistan, China, Bangladesh, and other countries.
• The question asks which single neighbour has the longest land boundary with India.
• The options are Nepal, Pakistan, China, and Bangladesh.
• We assume the learner is aware that India has a long and irregular border with several of these states.

Concept / Approach:
India's longest international land boundary is with Bangladesh. This boundary is highly irregular, with many enclaves and a long curve along the eastern side of India. It passes through states such as West Bengal, Assam, Meghalaya, Tripura, and Mizoram. While China and Pakistan have long borders with India too, the aggregate length of the India Bangladesh boundary is greater. Nepal has a significant but shorter border compared to Bangladesh.

Step-by-Step Solution:
Step 1: List India's major neighbours and recall approximate border lengths as learned in geography. Step 2: Remember that the India Bangladesh border is more than three thousand kilometres long and is often cited as the longest. Step 3: Compare this with the borders with China and Pakistan, which are long but not longer than the India Bangladesh boundary. Step 4: Recognise that Nepal has a comparatively shorter border. Step 5: Conclude that Bangladesh shares the longest international land boundary with India.

Verification / Alternative check:
Maps and official data from Indian government sources indicate that the India Bangladesh land boundary length is around 4000 kilometres, making it the longest among India's neighbours. In contrast, the borders with China and Pakistan are shorter. This quantitative confirmation supports the selection of Bangladesh as the correct answer.

Why Other Options Are Wrong:

• Nepal: Shares a long Himalayan boundary with India but not as long as the complex border with Bangladesh.
• Pakistan: The India Pakistan border is important strategically but is shorter in length than the India Bangladesh border.
• China: India's border with China extends along the Himalayas but is also shorter than the India Bangladesh boundary.

Common Pitfalls:
Many students incorrectly guess China or Pakistan because of frequent news coverage and strategic issues, associating importance with length. Another mistake is to underestimate the extent of the India Bangladesh border, which winds around many states in the east. To avoid confusion, remember that India's longest land boundary is with Bangladesh despite other borders often being more discussed in media.

Final Answer:
India shares its longest international land boundary with Bangladesh.