I have laminated maps and been able to fold them. Even better isto cut the map into the size youprefer, bind them with adhesive cloth (Chartex) and then laminate. Thereare also fluidswhich will waterproof maps.
I have used maps for years, treated in this manner.
I go to a variety store (walmart, target, etc) and buy a roll of clear adhesive shelf paper and apply to my map at home.
I found I need to do both sides to keep it dry.
as @hikermor said, the larger you try to do, the bulkier it will be. You can cut it into sections you'll actually be using, just use/carry one at a time. Store the other sections, and the rest of map, in a zip lock in your pack.
this works for me.
If your intent is to keep it dry, you may want to consider printing your map on waterproof paper (it only works with laser printers) which you can find online. If your intent is to keep the map from becoming unreadable at the creases, I would suggest cutting the map where you intend to fold the finished product, then either keep the finished pieces together OR laminate as one piece but allow a slight space between the pieces to allow for a fold in the lamination.