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. RN 1 continues north to N'guigmi more than 100 km. Maïné-Soroa, the other major town of the Region, lies less than 100 km to the west of Diffa. The border with Nigeria, at the Nigerian town of Duji, is 5.5 km to the south of Diffa. Diffa Airport lies to the north of the town.
In 2002, it was the centre of the first military uprising in the country since President Tandja Mamadou instituted civilian rule and led to a crackdown by the government against the civilian press.
Refugees from Nigeria fleeing violence from Boko Haram have crossed the border, and are living with local populations in Diffa and surrounding areas. As of 11 June 2014, the nearby "village of Guessere's population has doubled. Its new residents all come from a Nigerian village located 3 kilometers from the border." These refugees hid after an attack, and crossed a river to escape.NIGER REPUBLIC provide a lot of shelter, food and lots of material to the refugee more especially people from Damasak who were kept at gagamari. In early October, 2,200 more people arrived from the Nigerian village of Gueshkar. In the first ten months of 2014, "over 62,000 people" fled to the Diffa region to escape fighting in Nigeria.