In Baltimore County these votes may be "counted" beginning October 1, although the results are embargoed until after the polls close on Election Day. In this regard, it is important for voters to understand that, legally, "counting" begins when the ballot envelopes are opened, not when the votes are tallied.
The first steps in "counting" are to open the envelopes, check for signatures and dates, and compare the signature to the name in the barcode on the envelope. The ballots are then taken out of the envelopes, unfolded and stacked in neat piles to flatten out so that they can go through the voting machines to be tallied. When ballots are opened and when they actually start to go through the machines will depend on several things, including how fast they are coming in and how close to Election Day it is. Security is extremely tight.
Ballots cast during early voting: These are tallied beginning the day after Election Day (i.e., tallied beginning Nov 4).