Great demijon, I love the twist in the neck. Too bad Harry Pristis doesn't seem to be around anymore, he would be able to give you a good idea of the "when and where" on that one. My guess would be New York state, 1850s.
This is the oldest bottle that I have dug. It is a cobalt swirl scent bottle with a ground pontil and sheared neck made between 1800-1840. It realy made my day when it came out of the groung because before this guy my oldest was about 1885-1890. Realy old bottles do not come out of the ground alot here in Texas. You guys all have some very sweet bottles.