"Dendrochronology dating techniques have placed the cutting date of the timbers used on the bridge as late as 1838, and as early as 1831. Analysis of the General Land Office survey plat from 1839 indicates a major road, from Huntsville, Arkansas to Springfield, Missouri crosses the Osage Creek, near this location. Other historical records mention a road trending, in a northwest and southeast direction, through the approximate location of the site. Finally, the archaeological record indicates this was a beam type timber-frame bridge compatible with bridges built in the early- mid 19th century associated with mid-continent military roads. "
-- Abstract from an Arkansas Archeological Survey project by Aaron T. Lingelback, Jerry Hilliard, and Jared Pebworth, published in 2009: http://www.uark.edu/campus-resources/archinfo/UAF_JohnsonsFo...