Welcome to TNet. I too hail from Pennsylvania.
I would obtain a detailed map (a topographic map or a detailed atlas, such as the Franklin Atlases) for the area in which you wish to collect. I would note streams (ones that run year round, not the little seasonal ones), and then drive the area looking for farm fields near the stream. The best fields are near enough to the stream to access the water, but not so close or low as to be marshy. Then I would "cold call" the farmers and see if they will allow you to collect. Right now, with planted fields, most farmers will be hesitant to let you on, but you could ask for permission to collect in the future, especially in the spring, after the fields are plowed and disced. Farmers also may point you to other fields.
Occasionally one finds a productive field around some other water source, such as a spring. Such was the case with the famous Church Farm School site in Chester County, which unfortunately now is covered by a housing development.
Development, by the way, has drastically trimmed collecting sites in the Philadelphia area - one needs to go upstate where farming is more prevalent.
The really productive fields often are known to other collectors, so expect competition.
I have found that most landowners will let you onto their land if you are courteous, and if you don't abuse the privilege. The few times I have been denied permission have been a couple of instances where the landowner also is a collector, or where previous collectors have caused problems, to the point where the landowner wants nothing more to do with collectors.
ALWAYS ask permission before entering private land. I also observe an unwritten contract with the owner - I take nothing but artifacts, and leave nothing but footprints. For example, last spring I asked for permission to collect artifacts, and found a colonial coin (see my post "A R&D DAY in PA" below). I offered the coin to the farmer, telling him the coin rightly was his, since he only gave me permission to hunt artifacts. The farmer declined the coin but appreciated the gesture, and I will be able to return to that field again.
In my view, part of the unwritten contract is not to disturb the "status quo" by registering the site with governmental or archaeological authorities without the landowner's advance permission. Personally I think registration is a good idea, but it may have legal implications for the owner, so it is not fair play to register a site if the landowner objects. That effectively penalizes him for his kindness.
Good hunting. Artifacts are not easy to find, but they are a thrill when they turn up.
artorius
