Many of the attendees brought dogs with them to the Kennebunkport shore where the former first lady would often be seen in the early morning with her own canine companions while the family was at their vacation home in the Pine Tree State.
Some attendees at the memorial also donated children's books to be given to two local libraries and a children's hospital in her memory.
"That's our farewell to Barbara," said Diane Denk, who helped organize the memorial and often saw Bush on the beach in the early morning with her dogs.
Barbara Bush died Tuesday at her Houston home at the age of 92 and was laid to rest on Saturday at her husband's presidential library in Texas.
"Barbara was just a real stand-up lady," Denk said. "She was a good lady."
Sunday's mourners gathered in a large circle to share stories about their encounters with Bush on the beach.
"She was very philanthropic, she and George," Denk said. "They just, they loved their community, they loved the state, they donated to children's hospitals, they donated to just about every philanthropic cause around here."
One participant even reportedly made clear that Bush always picked up after her dogs on the beach, and never made it the job of Secret Service agents who could be seen trailing behind her.
A large poster board that featured a photo of the former first lady and several beach walkers and their dogs was signed at the memorial as some tossed flowers into the sea.