In article ,
C J Campbell wrote:
Just a wild guess, but I would think it is an artifact of the US
sectional/township system. Most property lines are along sectional lines (or
quarters of sectional lines) so runway length may be determined by what is
the longest diagonal that will fit on a square mile.

Either that or there is some FAA reg that involves runways of greater than
5000' that the designers wanted to take advantage of. But even there the reg
probably is based on the biggest runway you can fit on a section.

The main runway at BFI (Boeing Field) is also 10,001 ft. I have no
idea why. I always thought it was so that someone can claim: "Our runway
is over 10,000ft" without having to say equal to.