Washington-Baltimore Metropolitan Area

Here are my statistics for the Washington-Baltimore Metropolitan Area

County/Area	Area (sq.mi.)	Pop. (thous.)	GDP (est.) $billions
Inner Core
District of Columbia	61	618	105
Arlington County, VA	26	209	8
Alexandria (city), VA	15	140	5
Subtotal Inner Core	102	967	118
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Outer Beltway
Montgomery County, MD	507	972	35
Prince George's County, MD	498	860	20
Fairfax (city), VA	6	23	1
Fairfax County, VA	407	1101	41
Falls Church (city), VA	2	12	0
Subtotal Outer Beltway	1420	2968	97
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Exurban DC
Charles County, MD	643	147	4
Frederick County, MD	667	233	6
Fredericksburg (city), VA	10	24	1
Loudon County, VA	520	312	10
Manassas (city), VA	10	38	1
Manassas Park (city), VA	2	14	0
Prince William County, VA	338	402	10
Stafford County, VA	270	129	3
Subtotal Exurban DC	2460	1299	35
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Baltimore Area
Anne Arundel County, MD	588	538	15
Baltimore (city), MD	92	621	11
Baltimore County, MD	682	805	21
Carroll County, MD	452	167	4
Harford County, MD	527	245	6
Howard County, MD	254	287	9
Subtotal Baltimore Area	2595	2663	66
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Total Washington/Baltimore	6577	7897	315

Update:  Revised 7/2/2012.  I was confusing household income with per capita income.

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Another source has:
Baltimore-Towson, MD  $144.8 billion
Washington-Arlington-Alexandria $383.1 billion
for a total of $527.9