The post contains answer to questions “Which dam was first built in Pakistan? What is the name of dam that was built first of all in Pakistan?”
Which dam was first built in Pakistan?
Name of the first full-fledged dam that was built in Pakistan is Mangla Dam.
Though a few small dams such as Warsak Dam 1960 (Peshawar KPK), Mana Storage Dam 1961 (Ziarat Balochistan), Walitangi Dam 1961 (Quetta Balochistan), Baran Dam 1962 (Bannu KPK) and Rawal Dam 1962 (Islamabad) were already existed but the first major dam that was built by the country’s own government is Mangla Dam.
The Dam was built on Jhelum River in Mirpur district of Azad Kashmir and its construction work was completed in 1967. The Dam storage capacity is 7,251,811,000 Meters Cube (m3 ).
Source: Above answer is based on the information and data given by Wikipedia and Pakistan Studies.