Any idea? I found ones for other big States - such as CA, TX and so on - but none for MD(why?).  I want to take full advantage of what's available these days, and hopefully become a better fisher at the same time. So, who can help me please? 

I’m from Penna. and a few trips a year. The state of Maryland has a great DNR system. Call them. They will help. Have to believe it because they have a lot online compared to PA and many other states. I only fish a few tidal spots there and love the trips down. 

you mean Lake Bathymetry maps? Like contour lines and stuff? If that's what you mean, then Navionics Webapp would be your best bet.

Eddie, If your fishing from a boat does it have electronics? If so depending on brand there are some good maps available to you. I run Humminbirds and use Smartstrike on my units. It will give you all the lakes in Maryland along with some of the best places to fish on the lakes.