Not a country we’ve had that much to do with militarily really.
In 1805 Mungo Park (see Mali) set off to explore the Niger River and what was left of his expedition passed through what is now Niger in a canoe that he had named the ‘HM Schooner Joliba’. Unfortunately for him, what was left of his expedition wasn’t left very much longer, because they all died further down the river.
During the First World War there was a major Touareg rebellion against French rule in Niger, allegedly encouraged by pro-German elements. About 1,000 Touareg warriors attacked the town of Zinder, in Niger, just north of the Nigerian border. In response, we sent troops from Nigeria to help the French suppress the rebellion.