I always get mine from one of the local tacke shops. Try searching online. Waterproof is a plus. Look for one that is as recently printed as you can find. You want it to show as many points of depth as you can find, channel markers, boat ramps, obstructions, wrecks, secondary channels, in other words, as much detail about whats underwater as possible. Also remember the depths given on the chart are subject to change with the tide and weather. Just because the chart shows 3ft of water does not mean for sure there is that much there at low tide during a drought. Could be 1ft instead. Mine was made by GMCO Maps and Charts and was printed in 2001. It's getting a little worn and is taped up in a buch of spots, so I have been keeping an eye out for a replacement. Just have not found one I like yet.