I lived in a place in Bucks County, near Philadelphia, PA, that was on the border between suburban development and woodlands. There were about two acres of mowed lawn on our property and more in neighbor's places. There were several acres of abandoned fields and several acres of woodland on our property and neighboring property.
So naturally there was a lot of wildlife in the area. One day my sister went down the street to investigate screaming she heard. She reported she found a teenage girl standing on a picnic table screaming because she saw a mole. That girl would not like the critters we saw just a block from her place, mammals as large as deer and birds as large as Canada geese.
I once spent some time the woods, cutting the vines which grew on the trees, but I didn't notice any snakes in the woods. Once an old woman visited and said when she was a girl she went into the woods and was scared by seeing big snakes on rocks in the creek.
Naturally I sometimes saw small snakes on the place, garter snakes and similar types. I once saw a short, fat, ringed snake which I can't identify. And eventually big water snakes came to our pond - probably the type the old woman saw. They seemed to be northern watersnakes Nerodia sipedon sipedon. My brother in law said he killed a baby cottonmouth or copperhead on our place, and it was probably actually a watersnake.
The watersnakes were mostly in or near our pond. Sometimes they sunned themselves on the dock of our little pond. And once I saw about four mallard ducks sitting on one side of the dock and about six watersnakes on the other side.
And I never had any trouble with snakes.
As far as I remember, all the snakes I saw on our place were on the lawn or in the pond. Except one time we lifted up a stone slab and there was a little snake under it which looked right and left and finally made up its mind which way to slither off. I don't remember seeing any snakes in the woods, not even when looking at the creek where the old woman saw snakes.
So in my experience it is hard to see snakes in the woods or know how many might be in the woods.