hi Rachel . where i am not a bottle digger i do have a nice collection going, where i have found mine is under and in old houses and barns .
i spent around 10 years tearing down antique log cabins and seemed to always find 1 under every house .
Now this information may not help much but the guy i worked for doing the old cabins was a history buff and a very smart man , i remeber 2 locations he spoke of to find old bottles. pipes ect,,,
1 was a old factory where the workers would sit out back and drink /eat and smoke and throw there trash behind the factory, he said all old factorys had trash piles, now these are probally buried by now and will be hard to find.
2 was old african american grave yards , not actually in them but around them , he said it seemed there was always a trash dump next to a african american graveyard. keep in mind it needs to be a early grave yard not this century.
again i am not sure if this helps just information i remeber and it may not be 100% accurate but my old boss really knew his history so i think there is some truth to it.