We have seen projections that metro Washington’s current population of ~6 million will grow by 38% reaching 8.6 million by 2040. New Census 2010 data released for Maryland and Virginia give us an indication of how that growth is currently taking shape.

In Maryland four of the five most populous cities are found in the Washington region (Frederick being the largest of the four with 65000) though besides Baltimore (pop. 620000) most of Maryland’s population is found in its counties. Speaking of the counties two of the most populous counties are in metro Washington (bolded) while two others are sometimes included:

1. Montgomery County: 971777 (11.3 percent growth since 2000)
2. Prince George’s County: 863420 (7.7 percent)
3. Baltimore County: 805029 (6.7 percent – does not include Baltimore City population)
4. Anne Arundel County: 537656 (9.8 percent)*
5. Howard County: 287085 (15.8 percent)*

*Anne Arundel and Howard Counties lie between the Washington and Baltimore metro areas and are sometimes counted as part of either or as part of the larger combined Washington-Baltimore metropolitan area.

In Virginia none of the five largest cities are found in metro Washington (Arlington is technically a county) with the Hampton Roads and Richmond metro areas grabbing all the top slots. However when it comes to the counties metro Washington jurisdictions (bolded) make up a massive percentage of the state’s population. Note the extraordinary increases in some outer Virginia counties:

1. Fairfax County: 1081726 (11.5 percent growth since 2000)
2. Prince William County: 402002 (43.2 percent)
3. Chesterfield County: 316236 (21.7 percent)
4. Loudoun County: 312311 (84.1 percent)
5. Henrico County: 306935 (17 percent)

The District of Columbia has not yet received a breakdown of its population at the Ward level but it has passed the 600000 population mark and just experienced the first decade of growth since the 1950s. If trends continue Washington will soon be a larger city than Baltimore.