The board of elections is reporting with regular updates.
I should have remember that myself, but I got the link from Maryland Juice.
[10:16 pm] Addendum, county status page, to tell who has reported so far and thus who has left to report. Numbers for Montgomery are 68 out of 238 which is good news as the marriage equity question is scarily down to 51%-49%.
[12:39 Maryland Juice is calling it a win as is Maryland for Marriage Equality! We're at 940,507 for and 895,573 against, probably a few hundred thousand more yet to be added.]