This system assigned each major island a number, which increased in the downstream direction.
The numbering system was based on the premise that the islands were relatively permanent, static features when in fact the opposite is true.
Due to erosion and accretion, the islands in the lower Mississippi are in a constant state of flux, ever growing, shrinking, and at times disappearing entirely, particularly after major floods.
Some of what constituted it is now part of the floodplain near New Madrid, Missouri as the river's channel changed; the bulk of it has simply been eroded away.
For this reason, the Battle of Island Number Ten monument, which references this fact, is located on State Route 22 approximately three miles north of Tiptonville; the cemetery where some of the combatants were interred is across the river in Missouri.