I live in Herndon near Frying Pan Park. There was a posting on Journey North over a month ago by a neighbor in Franklin Farm (5 minutes away). I haven't seen anything.
A friend in Leesburg, VA (an hour away) saw a Monarch at Banshee Reeks in Leesburg, VA yesterday. Very few sightings. Last year, I had eggs on April 30. This year June is half over and I haven't seen anything.http://www.learner.org/jnorth/maps/Sightings_All.html
There's a drop down list to search for eggs, larvae, adults.