First and most important, as soon as I get a new map, I cut it up into pieces that can be filed in folders and stored inside my 17x12 weather-proof map case. The principle is never to have to fold or unfold a map, and always to keep them well enough organized I can always find the relevant detail map within 15 seconds without having to stop my vehicle.

Then I take another map that covers a larger area and draw the grid that represents the whole map that I just cut up. I draw lines where the cuts are and number the grid with letters and numbers (like 1a, 1b, 2a, etc). This then becomes the index map and goes in the front of the folder. For areas where I already have the base USGS maps (most of the areas I frequent), I use the same index numbers as the corresponding topo map so I can move easily between different types of maps that cover the same area.

As for notations on maps, I usually add GPS lines if they don’t already exist, and highlight them if they do. In some areas (national forests, especially) I keep detailed notes on the roads, like if they are paved or if they may become impassable in heavy rain, and any gates that I find. In some areas I transfer the lines of public land ownership as shown on the local resource (park) maps and as seen on the ground, to my topo maps which show greater detail than the park maps.

I mark all access points to public water, sometimes with notes on the details. On navigable rivers and creeks, I mark unmapped cut-offs, major blockages and manmade structures which front the stream. For some public areas that I frequent a lot, I’ll start with a 2x or 4x blow-up of the most detailed topo map and add in lots of features like good camping spots and jeep trails.

Note: This is all pre-mapping-GPS, which I am slowly transitioning to. I’ve been working with incorporating the GPS changes for 4-5 years, but it’s still not where it needs to be to totally replace my paper system. Soon, though, I think it will be (with its own paper-based back-up system to protect against power failure). For the last year, I’ve been using a PDA-based mapping-GPS system that looks very promising.