Hello,
Yes there is indeed gold in Maryland and Virginia. Back in the 80's I prospected Virginia for a a couple of years and even bought a small backpack dredge. I didn't use a metal detector for gold back then, only other treasures. I had a large collection of topo maps and other research material. Yes research land ownership and get permission. Dredging is OK in VA with proper permits and permission.
See this discussion for VA: Laws & Regulations for Dredging in VA:
http://au-prospecting.com/gold1/viewtopic.php?f=1&t=3643
For MD:
Maryland has strict property right laws. Mining, panning and prospecting must be done with permission from the property owner; otherwise, you are trespassing. Collecting of rocks is prohibited on State owned lands unless permission is obtained from the Maryland Forest and Park Service. On Federal Park property, site of many of the old gold mines, permission must be obtained from the Superintendent of the Parks prior to any panning operations. One other caution is that it is extremely dangerous to enter any of the old mine shafts or openings.
From:
http://www.mgs.md.gov/esic/brochures/gold.html
In Maryland around Simpsonville, The Maryland Mine (once richest gold property in Maryland) gold in quartz, with silver and pyrite. Woodbine, MD, several area mines. Montgomery County MD., Great Falls Mine, gold with tetadymite.
Now I found a pretty good nugget while panning a small waterfall in a Creek in Virginia. This nugget is big enough for the ATX to have picked it up. The are has dumps, pits and trenches. I'm working on getting permission again to go in there when I decide to spend the money on an ATX.
Another place is where Wilderness run goes into the Rappahannock river. There is an old smelter chimney there. I went in there with my brother via canoe launched at Ely's Ford.
There are many an adventure waiting for me and maybe a partner?
And lastly, the place I found the nugget, I found a huge quartz vein, had it assayed and the result was 1/4 ounce gold per ton of ore and 3/4 ounce of silver per ton of ore.
HH all
Frank