> we don't use leagues or furlongs. I know what a chain is because i have one, but that's specifically to measure land against a plat map. Every location in this country is based off common reference locations (there's a literal marker on the ground)

The same holds for more obscure unit prefixes in the SI system like dam (decameter) or hm (hectometer) in the SI unit system (as far as I am aware, the only common usage of the "deca" prefix is in Austria for "decagram" (dag)).

Nevertheless, even these obscure units fit the regular pattern perfectly:

1 km = 10 hm = 100 dam = 1000 m

- and this was my point.