A former cast member of the reality show "House of Carters," Carter was the married mother of an infant daughter when she died last Tuesday. She was also the sister of recording stars Nick and Aaron Carter.
An autopsy performed last week on Leslie Carter's remains proved inconclusive with officials waiting for the results of toxicology tests to determine the cause of death.
However, TMZ has reported Carter long battled an addiction to prescription medication and her family suspects she died of a drug overdose.
While her brother Aaron was among the mourners at the service Sunday afternoon, her other singing sibling Nick Carter was working and didn't make it to the funeral home or cemetery.
"I wanted to be at my sister's funeral, but my family has always had a complicated dynamic," Nick said in a statement to E! News without elaborating.
"I love my family. I want to thank everyone for all of their compassion and support that I have received during this most difficult time," he added. "There are so many emotions for me surrounding the loss of my sister. I am trying to stay healthy, positive and focused."
The service took place at Freay Funeral Home in Mayville, not far from the home of Leslie's father.
"It was a very wonderful and touching ceremony," a source told E! News.
Aaron Carter saluted his sister via Twitter Sunday before the service.
"The truth will reveal itself," he tweeted. "I Love you Leslie soo very very very very very much!! virtually no words. You will always be my best friend."