Election Director Dorothy Kaetzel said the number of absentee ballots requested so far was around twice the number of absentee ballots cast in the 2002 gubernatorial election.
A little more than 1,500 of the absentee ballots for Tuesday's election had been returned.
Election officials don't know yet how many absentee ballots will come back.
Ballots will be accepted as long as they are postmarked before Election Day.
Four years ago, about 2,400 Frederick County residents voted through absentee ballots, said Stuart Harvey, the county's election director.
As of late Tuesday afternoon, Frederick County had given out more than 6,000 absentee ballots and gotten back more than 2,500.
Statewide, as of Monday morning, a record 161,000 Marylanders had requested absentee ballots, AP reported. The number of absentee voters was 65,000 in the 2002 gubernatorial election and 138,000 in the 2004 presidential election, when turnout tends to be higher, AP said.
Tuesday was the deadline for voters to ask county boards of election to mail them absentee ballots. Voters can get absentee ballots in person or through a representative as late as Election Day, Kaetzel said.
She said the extra flow of absentee ballots might keep some local races up in the air for days. As an example, she mentioned the Washington County Commissioner race, in which a fifth-place candidate will win and a sixth-place candidate will not.
Another race expected to be close, she said, is the state delegate Subdistrict 2C contest between Democratic incumbent John P. Donoghue and Republican challenger Paul Muldowney.
Election records show that of the 927 absentee ballots requested in that subdistrict by late Tuesday afternoon, almost the same amount went to Democrats as Republicans.
However, Republicans already had returned a higher percentage of their absentee ballots.
Local boards of elections will count - or start counting - the first group of absentee ballots two days after the election.
Provisional ballots, which are given to voters whose registration is in doubt at the polls, will be counted Nov. 13.
A second and final batch of absentee ballots will be counted Nov. 17.