One of my favorite things to do is to go for weekend camping and fishing trips near DC. I have a ton of suggestions, but do you have an idea of what kind of area you want to visit? Mountains? Beaches? Ocean? Lake?
In the Chesapeake for croaker, bluefish, rockfish etc. go to Point Lookout State Park in Southern Maryland (about two hours). It gets crowded on weekends, but is absolutely beautiful, has good swimming beaches and great fishing. Bait and tackle available at the site and also at some shops in Lexington Park.
Lost River West Virginia has some good trout fishing, isn’t too crowded and has some great hiking, waterfalls and green forests to explore (two hours). You can also camp at Trout Pond and fish on the lake. I don’t think there’s gear available on site, but you can pick up all you need at Wal Mart in Front Royal on the way out.
Lake Moomaw in Virginia is a beautiful mountain lake with good fishing for bass, catfish and perch and great swimming. It’s a little far at four hours or so, but worth the drive and a good place to cool off in the summer.Tackle shop and boat rental on site.
And for surf fishing in the Atlantic and flounder in the sound, you can always try Assateague in Maryland (three hours).
Some other places to think about: Deep Creek Lake, Harper’s Ferry, Lake Anna, Shenandoah River State Park, Eastern Neck National Wildlife Refuge