WATERVILLE — No one knows exactly how long Waterville’s oldest resident has been here.

Many put her birth around the Civil War. Most think she watched in 1888, when Waterville was incorporated as a city. She was definitely there when Interstate 95 made its way to Waterville.

Since sometime in the 19th century, Ellie the elm tree has watched Waterville transform from her home in Castonguay Square. But now, it’s time for her to say goodbye.

For years, the city has been taking meticulous care of Ellie. She became particularly important after Waterville, known as the Elm City, lost most of its elms to construction projects and Dutch Elm Disease in the 1960s and 70s.

She’s long been believed to be the oldest and largest elm in Waterville, but despite a healthy past, Ellie has succumbed to what the city thinks is Dutch Elm Disease, and will be cut down later this month.

Dutch Elm Disease is a fungal infection, which blocks trees from receiving water and nutrients. The city is awaiting test results to confirm what killed its oldest Elm, but all signs so far are pointing to the infection which has wreaked havoc on elms across North America.

Mike Roy, former city manager, has known Ellie for his whole life. He named her during the years when his city hall office looked out at the tree.

Ellie’s survival as Waterville went through difficult times, particularly the loss of manufacturing, was symbolic for Roy, 74.

“That tree, to me, represented what our city was and continues to be,” Roy said. “It represented strength, and a way to say, ‘Well, the Dutch Elm Disease may have gotten just about every tree in the city, but not me.'”

Roy said even as Waterville has enjoyed what he called a renaissance over the last decade, Ellie served as an important representation of another time.

“Now that’s been taken away from us,” Roy said.

When Serena Sanborn, 51, manager of outreach and community partnerships at Waterville Creates, leads tours through the Schupf Arts Center, she introduces everyone to the oldest lady in town.

She thinks Ellie does something people need: remind them of their past and, at the same time, connect them to the natural world.

“This tree has seen the history of Waterville unfold. That makes me cry to think about,” Sanborn said, tearful. “It’s witnessed so much under its branches.”

At a farewell ceremony on Tuesday, Sanborn will help people create memories of the elm with prints, and she’ll be sure to make a print of Ellie’s massive stump once she’s been cut down.

Sanborn is also mourning the shade Ellie brought to Waterville’s downtown.

Like Roy and Sanborn, Linda Woods, 74, has lived in Waterville on and off since birth. But Woods really became aware of Ellie only when she worked in city hall.

She spent her lunch time eating in the shade the big tree cast across the green. And when she had meetings, if the person she was meeting was agreeable, Woods would relocate the gathering from her office to under the tree.

Roy, Sanborn and Woods all agree that Ellie is much more than a tree. Woods said memories of Ellie can serve to unify the city in a time of division.

The city will bid farewell to Ellie in “a celebration of life and legacy,” on Tuesday at 2:30 p.m. in Castonguay Square. Ellie will be cut down the week of June 22, and the city plans to plant a fir tree, which could double as a Christmas tree, in her place. Sarah Cross, assistant city manager, also wants to create a plaque for the area in Ellie’s honor.

Once Ellie is gone, locals will be able to count her many rings, and see just how old she was.