The US already has a presence in the capital Niamey, where it shares an airbase with France’s anti-Islamist force, Operation Barkhane.
MQ-9 Reaper drones are stationed there.
But the new facility, in the central city of Agadez, will give Washington greater ability to use drones against Islamist extremists in neighbouring countries like Libya, Mali and Nigeria.
A spokeswoman for the Pentagon, Michelle Baldanza, confirmed the US had agreed to pay for a new runway and “associated pavements, facilities and infrastructure”.
She estimated the cost at $50m but The Intercept, which first reported the story, said it is projected to cost twice that.
The investigative news site reports that it has obtained files that show the project is considered “the most important US military construction effort in Africa” and will be completed in 2017.
Drones, also known as UAVs (Unmanned Aerial Vehicles) or RPAs (Remotely Piloted Aircraft) are used by the military for surveillance and to drop bombs, in places where it is too risky or difficult to send a pilot.