If you go to this link ....
http://seamless.usgs.gov/ .....and click on the Elevation: NED 1/9 in the top box it will bring up a page with DATA Availability ( graphic )......click that black box and this will give you a little map that you can expand bigger to show the areas that are available for 1/9 sec arc DEM's. Orange is what you are looking for......green has no availability for NED 1/9
HTH.