You could check if there’s an Angie’s List for your area. I’ve had excellent luck with all the trade’s people I’ve hired after finding them there. Plus they may have a Wells and Pumps section, I would assume anybody found there can find a well.
Newer ones might have the ground-level cap, but the one at my parents’ house doesn’t. If I dig down at the right point, I’ll hit a manhole cover about two or three feet down. The well shaft is below that. And I sympathize with the OP. About 20-25 years ago, we had to locate the well in the middle of winter without knowing its precise location. It was not fun digging in frozen soil.
One thing to try is to locate where the supply pipe enters the house. You might assume that the pump is located in a straight line out from there. It can’t be too close to the house, so perhaps start digging forty or fifty feet out?
Try ‘utility locating service’ to find a call before you dig company. You might also try to look for the well cap or an electrical box near where the well is at. I don’t know about PA, but here all water wells are recorded by the state engineers office, they also may have the location recorded. If not, they can tell you who drilled the well so you can find out who the installer is and call them. You might also want to call any well service company instead of a plumber.
Look under “Well Service” in the yellow pages, or yellowpages.com. You can find well specialists. That’s what I did when the tank on my well lost pressure. I need to have my pump serviced, but it’s expensive, and I now have connection to city water to the house. I usually use the well for watering the horses and flowers.
Hardware store, but it won’t be able to see deep enough for a water line, as yours is probably below the frost line. It might help you find a well cap, which might be buried under something. Have you looked in the basement? Long ago, they drilled wells and built the house over it.
You probably have a pressure tank. Follow the source line into that and it will tell you in what direction to look.
Glad to hear you’re on your way to water. A fitting cracked on mine, like 5-6 feet below the ground. I was looking at thousands of dollars by the time they got a backhoe to the well, which included removing trees that had grown since the well was installed. I grabbed a shovel and got to work. Any movie that shows people digging a grave really glosses over how much work this is. Made me reconsider certain “plans” I had…