Georgetown Waterfront has several options. Took my kids to Farmer's Fisher's Bakers. The 16 year old girls spent an hour taking pictures before overlooking the water. Perfect spot!

What about the Wharf? Hanks Oyster Bar or something like that. They could eat there+ have them take the water taxi after lunch to Georgetown and pick them up there.

We live in MoCo but open to DC as well. Birthday is in early September and outdoor dining is preferred. My DD isn’t sure yet whether she wants to do a family thing or include a couple friends, so I’m just looking for ideas right now.