It can't be easily modified for handicapped accessibility, its basement cannot be converted into classrooms, and growth in the area is coming into Antrim Township, not the borough, she said.
The borough of Greencastle, which covers one square mile, is not growing, she said. It was able to support two Lutheran churches in the 1950s and 1960s but attendance began dropping in the 1970s, Thomas said. Fewer babies were being born and there was a general exodus from all churches, she said.
About 65 percent of Trinity's members live outside the borough.
"Trinity never really had a solid sense of its identity and who it needs to serve," Thomas said. "We've studied ourselves as a church and who we are as God's people. We believe our mission is to those people who are moving into the township."
She said the congregation, which averages about 50 parishioners who attend regularly, wants to build a new church on at least five acres in southern Antrim Township where growth is occurring.
So far, only a vote has been taken. No land has been purchased, and fund-raising for it has not yet begun, Thomas said. Construction could still be four or five years away, she said.
"We're going to start with a very minimal building and then expand in stages," she said.
More than 2,000 building lots have been approved in Antrim Township for the next three years, representing a population growth of 7,000 people,
"Statistics show that 10 percent of them will have a preference for the Lutheran Church, although today people are not loyal to any one congregation," she said. "People choose a church because of the people in the church and its programs and activities."
Berger's grandparents were charter members. She grew up in the church, was married in it, raised her three children in it and saw two of them get married in it.
"It's emotional for me to think about leaving here, but the building is not the church, the congregation is the church," she said.
If a new church is built in a growing area, it will get financial support in grants and loans from the National Lutheran Church Synod, Berger said. The synod will not support the church where it is.
"It we don't move, this church will have to close in four years. We won't have the money to keep it going," she said.