< but I'm wondering if the marker would be sufficient evidence?  Depends who placed it, I suppose?> I live near the intersection of 4 grids. It is in a subdivision. There is a bronze marker placed near the curb, explaining the meaning of the grid lines and longitude and latitude. BUT, the actual intersection is across the street, in someone's front yard, not at the curb, where the plaque is placed. You have to rely on your GPS, or one of several grid mapping programs that you can enlarge and do a print screen. Both will work. I use a hand held GPS for this and also for geocaching. Brad KC9UQR