The board looked at close to 940 ballots. It rejected about 20 for reasons such as late postmarks or missing signatures.
The board counted 828 ballots and put 90 aside to count next week.
The county commissioner candidates with the most votes on Tuesday also received the most absentee votes on Thursday.
Democrat Kristin B. Aleshire received 192 absentee votes, giving him an unofficial total of 4,774 votes. The other winning Democrats, in order of vote totals, were: Paul L. Swartz, N. Linn Hendershot, Brightman and Hardin.
Republican John F. Barr received 246 absentee votes, bringing his unofficial total to 6,226. The next four Republicans were: William J. Wivell, Terry L. Baker, James F. Kercheval and John C. Munson.
Wivell, Kercheval and Munson are incumbents. The fourth incumbent in the race, Doris J. Nipps, trailed Munson by 382 votes in the Republican primary, according to board of election figures Thursday morning. With absentee ballots, Nipps was 380 votes behind.
Washington County Election Director Dorothy Kaetzel said the board will count provisional ballots Monday. Provisional ballots are for voters whose registration is in doubt; officials decide later whether to accept the ballots.
Kaetzel said the board will count about 100 provisional ballots, plus about 45 ballots held back from Thursday's absentee count.
On Wednesday, the board will count the remaining absentee ballots postmarked before the primary but not counted Thursday. She expects a few. They will be mixed with 45 ballots held back from Thursday's count.
That means the board will have roughly 200 ballots to count next week.
The Washington County Board of Education race also wasn't affected by Thursday's absentee ballot results.
Six of the 10 candidates will move on to the general election. After Tuesday, Wayne M. Kretzer Jr. was in sixth place, 200 votes ahead of Gary E. Nally. With Thursday's absentee results, Kretzer's lead grew to 223 votes.