Diffa is a city and Urban Commune in the extreme southeast of Niger, near that country's border with Nigeria. It is the administrative seat of both Diffa Region, and the smaller Diffa Department. As of 2011, the commune had a total population of 48,005 people.Diffa marks the eastern end of the paved section of Route Nationale 1, the main east west highway across Niger, although the section between Zinder and Diffa is only partially paved in places.