The memorial was held in the community of Argenta, near Johnsons Landing where the slide occurred.
The slide claimed the lives of 64-year-old Petre Frehse, 60-year-old Valentine Webber and his daughters Diana, 22 and Rachel, 17.
A friend of the deceased, Tenise Trueman, says those in the community are doing what needs to be done to honour the victims.
The bodies of the Webber family were recovered in the days following the slide, but Frehse's body will likely never be found according to searchers.
The mountainside gave way on July 12 after a month of heavy rain sending a cascade of soil, rock and other debris through the remote community of 35 people.