In Indian physical geography, which of the following rivers is considered the longest river within India in terms of length flowing through the country?

Introduction / Context:
This question is from Indian physical geography and focuses on the major river systems of the country. Many exams ask about the longest, largest, or most important rivers in India. The phrase “longest river in India” in standard school level and competitive exam usage usually refers to the river with the greatest length flowing within Indian territory, rather than its total length including other countries. Knowing this convention is important for selecting the correct answer.

Given Data / Assumptions:
We must identify which river is considered the longest river in India from these options:

• Brahmaputra
• Ganga
• Godavari
• Krishna

We assume that the question follows the common exam convention of comparing lengths within India’s borders, not the entire international course of a river like the Brahmaputra, which flows through multiple countries.

Concept / Approach:
The Ganga (Ganges) is widely taught as the longest river in India when measured by the length of its course inside Indian territory. While the Brahmaputra is a very long river globally, a significant part of its length lies outside India, flowing through Tibet (Yarlung Tsangpo) and Bangladesh. The Godavari and Krishna are major peninsular rivers, with the Godavari sometimes called the Dakshin Ganga (Ganga of the South), but their total lengths are still shorter than that of the Ganga within India. Therefore, the correct approach is to recall that Ganga is the standard textbook answer to this question in most school and competitive exam contexts.

Step-by-Step Solution:
Step 1: Recall that the Ganga originates in the Himalayas and flows across northern India before entering Bangladesh, covering a very long distance within India. Step 2: Remember that the Brahmaputra has a long course, but much of it lies in Tibet (as Yarlung Tsangpo) and later Bangladesh; the Indian portion is shorter than the Ganga’s Indian segment. Step 3: Compare the lengths of major peninsular rivers like the Godavari and Krishna, which, while long, are still shorter than the Ganga’s total flow in India. Step 4: Recall that school geography often states simply: “The Ganga is the longest river in India.” Step 5: Choose Ganga as the correct answer from the options.

Verification / Alternative check:
Verification can be done by remembering typical exam prep tables that list the main rivers of India, stating approximately that the length of the Ganga within India is about 2,500 km, whereas the Indian stretch of the Brahmaputra is shorter. Meanwhile, Godavari and Krishna have lengths of roughly 1,400–1,500 km and around 1,300 km respectively. These approximate figures may vary slightly by source but consistently place the Ganga at the top for length inside India. Almost all standard geography books and competitive exam guides reinforce that the textbook answer to “longest river in India” is the Ganga.

Why Other Options Are Wrong:
Brahmaputra: Although very long overall, a major portion flows outside India; exam convention usually does not treat it as the longest within India.

Godavari: The longest peninsular river and called Dakshin Ganga, but still shorter than the Ganga in total length.

Krishna: Another major peninsular river, yet its length is also less than that of the Ganga.

Common Pitfalls:
Some candidates may overthink the question and choose Brahmaputra, considering total river length across all countries. Others may mistakenly recall Godavari as the longest because it is the longest in peninsular India. To avoid these traps, focus on the standard school level framing: when the exam simply says “longest river in India” without further qualification, the accepted answer is Ganga, with Godavari as the longest in the south and Brahmaputra recognised more for its massive water volume and international course.

Final Answer:
The longest river in India in terms of its length within the country is the Ganga.