Trans-Saharan trade
The cities of southern Niger and Northern Nigeria have been linked in the Trans-Saharan trade going back to the medieval period. Cities such as Kano and Katsina have long been the southern terminus of trade networks which sustain much of Niger's economy. Nigeria benefits from the trade and agricultural sales (especially Nigerien cattle taken to Nigerian markets), while Niger's most direct routes to overseas trade are through Nigeria's and Benin's railway systems.