The top five vote earners by the end of Thursday's count will win nominations.
They will face Republican slate members Ruth Anne Callaham, the Rev. Haru Carter Jr., Scott D. Hesse, Dan G. Kennedy and Torrence M. VanReenen on May 17.
The primary also resulted in an apparent win for Republican slate mayoral candidate Richard F. Trump. If his victory stands after the absentee ballots are counted, he will face incumbent William M. Breichner in the general election.
Hendershot, who was elected to council in 2001, said he believed there were several possible reasons for his loss, including his criticism of the proposed move of Washington County Hospital and voter apathy.
While voter turnout this year was higher than in years past, election officials said only 14.5 percent of registered voters came to the polls Tuesday.
"I think this council had one tremendous thing in common ... and that was to make Hagerstown a better place. I can't say that about some of" the other candidates, Hendershot said.
Specifically, he labeled the Republican slate as a group catering to the hospital move and developers who would benefit from the move, and said those candidates will owe their donors political favors if they are elected.
"I've never compromised what I thought was best," Hendershot said. "It seems like common sense doesn't count right now."
Cromer, who was at the election board offices Tuesday night as the results were announced, said she and supporters, including union members and personal friends, spent the day campaigning.
After learning of her primary victory, she said, "Thank God!"
She said she was picked because "I think I have a lot of people that believe in me."
Parson, who was reached by phone, said she was at a neighborhood gathering, and "I would not have wanted to receive the results anyplace else."
Parson, the first black Democrat to run for City Council since 1973, said her apparent primary victory not only "means everything in the world to me," but shows she has received support not only in black neighborhoods, but throughout the city, for which she credited the civil rights movement.
The last black Democrat who ran for City Council is believed to be Robert H. Kelsh in 1973. He lost in the primary election. The last black candidate to win a nomination was Republican Leonard W. Curlin in 1961. No black has held a council or mayoral seat in Hagerstown.
Tuesday's contest for the five Democratic council nominations pitted four incumbents against five political newcomers and one candidate who hadn't had a successful run since the late 1970s.
Aleshire, 29, was the youngest candidate, and the oldest was former councilman Ira P. Kauffman Jr., 72. The current council established a rental-home licensing program that requires regular inspections of rental homes.
The council members also claimed victory in having established an annexation policy, which was tested in a court case brought by the Washington County Commissioners.
City officials see annexation - expanding the city line - as a critical factor in expanding the city's tax base, and therefore spending abilities.
The current council has taken political hits on subjects such as the proposed move by Washington County Hospital and a lack of communication between city, county and state government.
Critics say the council has delayed the hospital move and spent nearly $300,000 last year on consultants, who themselves were critical of hospital plans being reviewed by state officials. Hospital plans have yet to be approved by state officials.
Council members defend the expenditure, however, saying they were looking out for the interests of both city taxpayers and hospital patients.