Fourth Principal Meridian Initial Point

This is one of the original 37 or so "Initial Points," survey points established between the late 1700s and mid 1950s to anchor the landscape of the USA to a cartographic grid. This meridian was established in 1815, initially to survey a relatively small area, lands in the northwest corner of Illinois, mostly between the Illinois River and the Mississippi, that had recently been acquired from the Indians. The Initial Point was originally established on the banks of the Illinois River, near Beardstown, but erosion, followed by engineering of the river channel, erased any physical evidence of it. The site has never been re-monumented. The northwestern corner of Illinois was surveyed by the Fourth Prinicipal Meridian, while the rest of the state was surveyed ten years earlier by the Third Principal Meridian. The Fourth Principal Meridian continues north into Wisconsin, and was used for the survey of that region as well.