J.J.
Hi M., I have a 7 month old daughter and live in Ashburn (Brambleton to be more specific). I am part of a playgroup on YahooGroup that is made up of moms around Loudoun County, Ashburn/Leesburg/Sterling area primarily, newmomsgroupgraduates. Feel free to look us up and join.
Most of us met attending a New Moms support group at Loudoun Hospital, and all of our children are around 6-10 months old. Not all of the moms work, but several of us do work part or full-time. I work 4 days a week. The group meets often for playgroups, though only occasionally on weekends. When we do meet on weekends, husbands are often invited and we have a potluck BBQ. We've also recently started a book club for the moms and a once a month mom's night out. You're welcome to join us for the next get-together. Like me, you probably won't be able to make it to many of the playgroups, but it'll give you a chance to meet some of us working moms in the area and find some playmates to get together with at other times.