"Monroe Furnace"

"Pioneer Furnace"

Brady's Bend Works, three furnaces remain in various conditions.  

Helen Furnace, stack has been completely restored, ruins of steam engine house remains.

St. Charles Iron Ore Furnace, 1/3 of structure remains.

Covered by the lake during most of the year.

Etna Furnace, Stack is complete and stabilized, several associated buildings remain as well.

Very different construction from that of American furnaces.

Most of the cut stones have been removed, but most all of the brick inner lining is still standing.  A very unique ruin.

Furnace in good condition, museum on site.

Bullion Run Iron Furnace, Front of stack has fallen, but a great deal still remains.  DO NOT ENTER THE RUINS!

This is a list of caches that I know are hidden in or around blast furnace ruins.  The list will be updated as more people complete the challenge.