A couple of the older maps with grids

River crossing -

 with a half inch grid overlay making it in effect A2 - 22" by 32"

This is a map I have published before without the grid.

once again the base image for the Map is A3 but I think it works and it would be simple to have it printed out A2 as a battle mat

with a quarter inch grid making the map in effect A1 44" by 64"

I will do some new work latter but I hope that you get the idea