If you're looking for a meeting place or a good stop around ½ or halfway between Ashburn and Newark, you can try Wilmington, DE, which is about 2 hours northeast of Ashburn, or about 2 hours southwest of Newark.
Other possible places to stop near the midpoint include Elkton, and Newark.
About ¼ or a fourth of the way, you can stop at Baltimore, MD. This is almost an hour east of Ashburn.
About ⅓ or a third of the way, you can stop at Essex, MD. This is about 1½ hours east of Ashburn.
About ⅔ or two thirds of the way, you can stop at Philadelphia, PA. This is about 2½ hours northeast of Ashburn, or about 1½ hours southwest of Newark.
About ¾ or three fourths of the way, you can stop at Trenton, NJ. This is about 3 hours northeast of Ashburn, or almost an hour southwest of Newark.
If you drive straight through without stopping at all, the total distance is 248 miles. The distances shown above don't include local roads to get into each town, so if you're planning a long road trip, make sure you factor in traffic and road conditions, rest stop breaks, and interesting detours along the way. If you're in a rush, you can do the trip with zero stops, and your total travel time would be around 3 hours, 55 minutes.