Transfer of territory from one country to another

What are some recent examples (post-WWII) of territory being transferred from one country to another?

I’m interested in examples that meet the following criteria:

  1. Before the transfer, the territory was recognised by both countries as being an integral part of country A (not a disputed territory)
  2. After the transfer, the territory was recognised by both countries as being part of country B (no dispute as to its status)
    I’m not interested in examples of territories becoming independent or losing independence.

Slovakia and the Czech Republic.

Do you want violent transfers, nonviolent transfers, or both?

It didn’t actually get done, but could have.

Do reunifications count? If so either Vietnam or Germany would count.

There is also the “Bantustans” in South Africa but they were not recognised as seperate countries by anyone except apartheid South Africa, so don’t really count:

Either, as long as the transfer of territory is legally recognised by both parties.

Reunifications and splits do not count. I am talking about cases where country A and country B continue to exist but a certain parcel of land that was part of country A is now part of country B.

The India-Bangladesh land swap is an example.

There is an island that gets transferred back and forth between France and Spain every six months, and has done so for the last 350 years.

In the 1960s and 1970s the U.S. and Mexico made some adjustments to resolve a longstanding boundary dispute along the Rio Grande:

You might also include the transfer of the Panama Canal Zone from the U.S. back to Panama.

The Canal Zone might not count: It was always recognized as a part of Panama, just a part of Panama that had special arrangements with the US.

No mention yet of Hong Kong being transferred from the UK to China?

Belgium and the Netherlands have fiddled with their border in recent years:

Belgium–Netherlands border - Wikipedia

The territorial swap saw Belgium giving a total of 40.45 acres of land to the Netherlands comprising two uninhabited riverine peninsulas, previously cut off from “mainland” Belgium by Dutch territory, known as Presqu’île de L’llal and Presqu’île d’Eijsden. In return, the Netherlands gave Presqu’île Petit-Gravier which was 7.63 acres in size, to Belgium.

Note that this involved less than 50 acres and approximately zero people. Still, I think it meets the criteria.

Along with Portugal return of Macau.

I’d say Hong Kong and Macau do not meet the requirements of the OP, as the PRC heavily disputed the legal status of both territories.

Also Hong Kong and Macau were colonies, not integral parts of the Portuguese Republic or the United Kingdom respectively.

This process of transferring land from one country to another by means of agreement is called a cession in international law. It’s not super rare in Europe for such things to happen; because European countries generally have quite crooked borders, it happens once every few years that some border is straightened by swapping pieces of land between neighbouring countries, but such processes usually occur on a very local level with small parcels. Somewhat recent examples that I can think of occurred were the various land exchanges conducted between West and East Germany in divided Berlin during the Cold War; here is an article about them.

Since OP stipulated post-WW2, the territory that immediately came to mind was that portion of Germany east of the Oder-Neisse line. After Germany’s defeat and partition, the DDR agreed in 1950 to give that portion to Poland, while West Germany refused to recognise the new border until 1970. Even afterward this was one of the sticking points against German re-unification as then-Chancellor Helmut Kohl suggested that the territory should revert back to Germany. The final border treaty, recognizing the former German territory as belonging to Poland was only signed between (united) Germany and Poland on Jan 16, 1990.

I think that’s not strictly speaking a cession. East Germany did not cede territory to Poland; it recognised a border that had already been drawn by the Allies after the defeat of Germany. The treaty text itself calls this the existing border (bestehende Grenze), indicating that East Germany did not lay claim to this territory prior to the treaty.