Annapolis.. Can't say past there cause I haven't been past.

That said, the stock charts show channel markers for all the channels, but without a lot of detail. i bought the card and all markers are now in color (reds and greens) and have numbers.

By the way, I bought a 78CX and returned it. Had ZERO marine info without spending several hundred more dollars. More dollars than the 76 cost new. Cities? yes. geocaching stuff? oh yes. Marine? Bare water, zero channels at all