Using information from the Bureau for Investigative Journalism, the people at Public Intelligence have created a Google Map showing all the United States drone bases in Pakistan, some of which are vital for the support of US military forces in the area.
Take a look.
Some of the bases are no longer in use. According to the information from the Bureau for Investigative Journalism, the Shamsi base was used by the CIA. You can check out the interactive Google map at Public Intelligence.