Hey there!
If you look at the chart, you'll see that when you open it up, the chart is divided by two folds - one verticle and one horizontal - into four sections. Up in the top of the page, you'll see a city and a number. Let's say it says 4 Elizabeth City. Now, you'll notice that around the chart, it'll say 4A, 4B, 4C and 4D (reading left to right, top to bottom). Now, you can kind of identify a particular area on that chart. Example, on L-38 of the Jepp chart, panel 4B (or P4B)has the NORTN intersection. Pretty useless knowlege, huh?
Well, remember, Jepp gives you all of the chart NOTAMS. When you get those enroute chart NOTAMS, they'll list something at the end of the NOTAM like "Norton Intersection decommisioned, P4B". Now, you know exactly where to go for that info.
Another use? Look on the "Communications Tabulations" section at the end of the chart. After each facility, it will list the location (on the chart) of that particular facility.
Pretty neat, huh??