Early group presidents included prominent businessman J.V. Jamison Jr. and Maryland Gov. William Preston Lane.
Party guests are asked to wear "full dress," which means white tie, white gloves and tails, said Mason Hendrickson, club president for the last four years.
Among the guests Saturday was Norman Holzapfel, 81, who was attending the event for the 65th time. Asked if he minded dressing up for the event each year, he asked what else he would do with that outfit.
Sitting next to Holzapfel was Col. Henry Miller, 87, the oldest Assembly Club member.
Miller joined the Assembly Club in 1929 but wasn't an active member from 1934 to 1979 because he held jobs that took him away from Hagerstown, he said.
Miller and Holzapfel were in Junior Assembly, a related organization for residents still in high school or college, and both of their fathers were in the Assembly Club before them, Holzapfel said.
Both indicated concern about the Assembly's future.
"I think it is a thing of the past," Holzapfel said. "The tradition is becoming passe."
"We need more younger people," said Miller. "Pretty soon we'll be out of business."
While there are young members, they are not as active, he said.
Steve O'Farrell, 29, said people of his generation would be more involved if they knew more about the organization.
O'Farrell, a member for three years, said he likes attending the annual party, especially because it gives him a chance to don fancy attire.
"It is like putting on a uniform," he said. "It is something fun and unusual."
Assembly membership is limited to 125. New members are nominated by existing members.
Sometimes debutantes are presented to society during the party. There were none this year, however.
The evening included a reception, followed by dinner and dancing.