Here's my wellhead.  Do I need to worry about this freezing in the winter?

Wife says no.

No. mine is exactly the same and it has never froze up here in the mtns of western PA. The pitless adapter is down about 4-5 feet usually wich is the depth at which the pipe to the house is run it is usually located far enough underground to prevent freezing. The cap and exposed casing dont have any actual water in them (you can undo the nut on the side and lift the lid and look down the well no problem) the water depth should be printed under the cap and unless its like under 3 feet to the water no way its gonna freeze.

that one looks like it was just drilled.

Thanks for the info.  

Dang.  Looks like the wife was right for the SECOND time.

That picture was taken about a year ago right after it was drilled.

I'm going to say the water line is about 4 feet below ground line so it sounds like we're GTG.

yep should be GTG....

Though the paranoid voice in side me worries about four standard bolts being all that is between me and someone dropping something nasty down my well

The only thing I can recommend is if the bolts on the well cover aren't stainless steel, that you replace them with stainless steel bolts.  Just in case you have to open it up sometime down the road.