Channel 4 News discovered yesterday that not everyone in Britain is exactly clear where the border between the Republic of Ireland and Northern Ireland lies.
We've created a simple tool to see how well you do when put to the test?
Simply mark the Northern Ireland Border. It doesn't need to be perfect, just a line will do.
Once you've drawn your line, hit submit to see how you did.
Having trouble? If so click here to open the tool in full screen.