I am from ND and I know about cold. The shaped foot warmers (like hand warmers were used by me for the first time this year. Combine that with a GOOD wool sock.Do NOT go cheap on your wool socks they last a life time (almost) and the quality of wool makes all the difference. I will even put poly propolyne socks on first, then wool socks, and if it is wet, goretex socks.

Boots. If you are walking you need a sole that does not get HARD when it gets cold -- Rocky boots are the worse I have ever had. Cabelas "ice breakers" are not sold any more, but they or their great. I use Vasques when it is not real cold. Leather prefered with gore texliner.

For really cold still hunting I use Cabelas rubber boots with the MAXIMUM thinsulate rating possible. 1600 is what my boots are.

Now to get a head start on it all find a electric boot warmer. They come with extensions for tall boots. At night put them on there and in the morning they are warm AND dry. Dry is a real key to keeping your feet warm.

Now, if you are in snow and walking hunting, you need leggings (gaitors). For you southern boys these are today made from cordura and have a hook that clip into your shoe lace, bungee type cord that goes under the boot in front of the heel. The codura goes around your entire leg with a zipper in the back and run up to just below your knee. Then a flap buttons over the zipper. The best ones that I have found have a draw string at the top that tightens so they stay up (I use a spring loaded cord stopper that keeps the string tight and the gaitors up. I first run into these hunting in Montana and soon found they adapt to lots of hunting situations. For those quiet sneaky stalks, I have a pair that are not cordura but quiet cloths that are very quiet.

The other thing I have found if I am going into a tree stand and it is cold (I have sat in them down to -30 F) is to walk farther to the stand as if you get your body core warm your feet stay warm.

Good luck and stay warm.