Nice find.  Outside of  western Maryland, eBird has only one July report 
of the species in Maryland (July 2001 by Bonnie Ott in Howard County).  
Please consider submitting your observation to the eBird database if you 
have not already done so.

Good birding!
Jim Moore
Rockville, Maryland
PLEASE REPORT YOUR BIRD SIGHTINGS to http://ebird.org/

On 7/12/2010 8:25 AM, Don Simonson wrote:
> My wife Marcia and I  saw an adult DARK-EYED JUNCO on Saturday evening July 10; at the cul-desac at the end of Springfield Road in Darnestown, Montgomery County. It was foraging on the edge of a driveway and hopping about in a low evergreen.  I dont recall seeing ever one before in Montgomery in July.
>
> Good birding-
>
> Don Simonson, Darnestown, Montgomery Co.
>
>