I did not expect this to just be a simple mistake, especially one that's been around for decades. Makes you wonder what other kind of basic facts are wrong.

In the age of satellites, computers, Google maps and the like you would think a mistake like this would be impossible to persist for so long.

These kinds of issues have existed since the first human started recording what they owned, and will probably continue plaguing us until the last one dies.

A bunch of countries are suspected of undercounting their population because so many people are living "off the grid" or deliberately overcounting to get more funding. Probably some of the cases are real and some are just conspiracy theories.

Imagine how much of published science is statistically significant only due to clerical errors and mistakes in calculation...

(See e.g. The misreporting of statistical results in psychology journals; Bakker, Wicherts; Behaviour Research Methods; 2011.)