A PA28 PLT VIOLATED THE DC ADIZ.

Narrative

OBTAINED WX BRIEF FROM MILLVILLE FSS; STANDARD VFR BRIEFING FROM FWN TO OMH. ASKED ABOUT WASHINGTON AREA TFR'S. DEPARTED FWN. RTE OF FLT WAS DIRECT; OVERFLYING FDW; THEN UNDER THE WESTERN OUTER CLASS B RING OF DULLES AT 3000 FT MSL DIRECT OMH. I SQUAWKED 1200 ENTIRE RTE; AND DID NOT CONTACT ATC; BECAUSE I WAS UNDER DULLES CLASS B AIRSPACE ON THE W SIDE. ACFT IS IFR GPS CERTIFIED. MY FLT PLAN WAS WELL PLANNED USING WEB SITE TO AVOID P40; R4009 AND ADIZ. MY RTE WAS VERIFIED BY THE GPS AND PILOTAGE. I AM IFR RATED; BUT CHOSE TO FLY VFR. MY RTE WAS 20-24 NM W OF THE WASHINGTON ADIZ. UPON LNDG AT OMN; LINE PERSONNEL GAVE ME A PHONE NUMBER TO CALL. I CALLED AND SPOKE TO THE SUPVR AT POTOMAC TRACON. HE INFORMED ME THAT I HAD FLOWN THROUGH THE WASHINGTON ADIZ. HE ASKED ABOUT MY RTE OF FLT; DEP TIME; ETC. HE SAID THAT I MAY BE GETTING A PHONE CALL FROM THE FAA. A C172 LANDED JUST PRIOR TO ME AT OMH. I DO NOT KNOW WHERE HIS FLT ORIGINATED. PERHAPS THE LINE PERSON WAS SUPPOSED TO GIVE THE C172 THE PHONE NUMBER TO CALL. I CANNOT SEE HOW TRACON HAD ME IN THE ADIZ WHEN I WAS AT LEAST 20-24 NM W OF IT. I WOULD NEVER PURPOSELY FLY INTO AN ADIZ WITHOUT FIRST OBTAINING A CLRNC.