Geographically, Pakistan can be divided into three regions: the lowlands along the Indus in the south and east, the arid plateau of Baluchistan in the southwest, and the mountains of the north. The provinces of Punjab and Sindh, in the east and south, are well irrigated by the Indus and its tributaries. The land is fertile and produces most of Pakistan's food. This area, which includes the cities of Karachi, Islamabad (the capital), Lahore and Rawalpindi, is the most densely-populated in the country.

The southwestern province of Baluchistan covers almost half Pakistan's territory. The land consists of a stony plateau, sparsely populated and very dry. Outside of the provincial capital of Quetta, travel in Baluchistan is extremely restricted.

Pakistan's mountainous north contains the second tallest peak on Earth, K2 (28,250 ft., 8611 m), and over 300 glaciers. Three great mountain ranges stretch across this part of the country: the Himalayas, the Karakorams and the Hindu Kush. The region's topography is constantly changing, as frequent earthquakes help the mountains grow at the remarkable rate of 7 mm (1/4 inch) a year.

Pakistan's climate varies according to elevation. April through September are the most pleasant months in the mountains, although they bring oppressive heat to the low-lying plains of the Indus Valley, where midday temperatures can exceed 40 degrees Celsius (100 degrees F). December through February are the coolest months, as lowland temperatures drop to between 10-25 degrees C (50-77 degrees F) and the air in the mountains falls below freezing. Monsoons reach the southern areas of the country in late summer, although precipitation is minimal in Baluchistan and in the north and limited in most of the interior.