Islamabad is the capital city of Pakistan. It is the country's tenth-most populous city with a population of over 1.1 million and is federally ad…Islamabad is the capital city of Pakistan. It is the country's tenth-most populous city with a population of over 1.1 million and is federally administered by the Pakistani government as part of the Islamabad Capital Territory. Built as a planned city in the 1960s and established in 1967, it replaced the adjacent Rawalpindi as Pakistan's national capital.