Hundreds of locals are expected to congregate at the Eureka Stockade Memorial Garden from 7pm.
The 51-year-old, who was a well-known member of the Ballarat theatre scene, failed to return home from an early morning run on February 4.
Ballarat Mayor Des Hudson told 9News tonight would be a “fairly solemn event” that would give people the time to reflect and mourn the loss of the 51-year-old.
Residents will be invited to hold up their phones or light up a candle.
“The reach of this story in relation to Samantha, who set out for a run on a Sunday morning and should have been able to do that, yet did not come home.
“The tragic news that came through yesterday confirmed all of our fears.
“I had someone reach out to me that while she could not be there, she would be lighting a candle and placing it in her front window.”
The community has been heavily involved in the search for Murhpy, with groups of people gathering weekly to search nearby bushland.