Worst maps ever
Here are a couple of candidates:
1. A map of Mason's Neck near Washington, DC, used sometime in the winter of 1974. It was a copy of the USGS, needing various corrections. I don't know what the copy process was, but every fold in the map, even a gentle one, removed the little strip of map along the fold. I believe I finished, though it was a race to get done before the map disappeared completely.
2. Our first road trip to a DVOA meet, Blackbird State Forest in Delaware, a fine area lacking only in features and a map. The start, #1, and the finish were all off by several hundred meters. On the other hand, legs 2-3 (north on the paved road to the telephone pole at the road junction) and 3-4 (east on the paved road to another telephone pole) made good use of the best terrain and most accurate parts of the map.