Thanks @hibernicus. I should have figured there’d be a wiki-list of them.
I hadn’t realized that Florida had been purchased. That makes 5 purchases by the US, not counting those of nonincorporated territories.
ETA: Reading up on it a little more. The US didn’t actually send any money to Spain. Instead, the US settled claims by US citizens against Spain up to $5 million.
It won’t be quite the same as in 1922, though. 1922 was an example of secession - part of state A leaves and becomes wholly new state B. But if NI leaves the UK and joins Ireland, this will be cession - no new state coming into existence, but an existing state succeeding to the rights/obligations of the UK in respect of NI. That raises a set of legal and practical issues which is only partly similar to the issues that were raised in 1922. In particular the “disentangling of finances and debts” will play out very differently.
India ceded about 5,000 square miles of land to Pakistan in 1972 that it had captured during the 1971 Indo-Pakistani war. It was not “disputed” in the sense that Pakistan acceded to India’s claim to the land via its unilateral surrender, but it was captured territory rather than integral Indian territory.
South Africa ceded the city of Walvis Bay to Namibia in 1994. The situation is a bit complicated: South Africa already owned Walvis Bay before taking Namibia (then known as South-West Africa) from the Germans in 1915. SA then governed Walvis Bay as part of SWA/Namibia for several decades, before reasserting direct control as Namibian independence approached. Namibia became independent in 1990, and maintained a claim on Walvis Bay, but South Africa only agreed to transfer it in 1994.
Rupert’s Land was not sold to Canada. The Hudson’s Bay Company surrendered its trade monopoly charter back to the British Crown, the Crown transferred jurisdiction of the territory to its colony of Canada, and Canada paid compensation to the HBC for the surrender of their charter.
On doing a search, it turns out I’d asked the question about countries selling land a few years ago and had forgotten that I had. However, no one in that thread contributed the wiki-list that hibernicus did in this thread, so it was good I asked again.
Rupert’s Land was given as such a sale in that thread and we argued about it. I’m sure that’s why I mentioned it in my post. I may not have remembered the thread, but I remembered the arguement to some extent. Anyway, argue with the people in that thread who thought it was a sale of sovereignty.