I got a bit carried away in researching the history of this 
Twain-related landmark, but for those interested, here is a rewrite of 
my entry on this location in "Twain's Geography".  The early days - up 
to and including the Civil War drew the interest of some eminent authors 
of those times. https://twainsgeography.com/location/cairo-il

/Unaffiliated Geographer and Twain aficionado/