The changing nature of geography plays a critical role in the planning and execution of military missions. Geography as a subject combines both the physical and human elements and the rapid transformation of the landscape owing to climate change, and the corresponding cultural impact has to be seriously considered in the environment-security link. Lessons from military history point to the fact that ‘geographical ignorance’ can be perilous. This article analyses from the Indian context some of the specific geographical factors and their relationship and influence in planning and conduct of military operations.