The USGS maps division has now digitized a lot of it's content and now that's available via the National Map Viewer. Think of it as the Google Maps of all the USGS Map stuff. Not quite a slick and fast as Google Maps but it's a whole lot more detailed and has tons of information.
|The full map|
|A topo map overlay. None of those rivers hold fish|
|You can zoom in to "normal" topo map scale|
Also, don't miss the historic maps collection.
|1930 Map of Long Pond|
None of those streams hold fish either.