Monroe Station was actually the RR Depot at Monroe City MO
(Hannibal & StJoseph RR "H&SJ").
You will find quite a lot of info on this battle on the GenWeb site for Monroe Co MO .. search "MOGENWEB" then click on Monroe County.
Also consult the 1884 "History of Monroe & Shelby Cos MO"
Paul Jackson
of Monroe Co MO