Advia Credit Union, a billion-dollar cooperative formed by a merger effective Jan. 1, plans to expand its field of membership to include the entire state of Michigan and counties in Wisconsin and Illinois.

The 21-branch institution is based in Parchment, Mich., hometown of First Community Federal Credit Union, the surviving $700 million credit union that announced plans last summer to merge the $280 million E & A Credit Union in Port Huron, Mich.

The headquarters will remain in Parchment, a suburb of Kalamazoo, Mich., in south-central Michigan.

Advia has more than 100,000 members and serves a field of membership with more than 10 million residents, the credit union said. The name change was effective Thursday.

“The advantages of membership with Advia Credit Union will focus on community, trust, innovation and convenience,” said Advia President/CEO Cheryl DeBoer, “in other words – giving, investing, volunteering, educating, advancing, improving, and dedicating ourselves to the financial wellbeing of our members.”

DeBoer had been president/CEO of First Community. In the release announcing its new name on Friday, Advia said it plans to expand its membership to anyone who lives and work in Michigan.

In Wisconsin, membership will be available to anyone living or working in Rock, Green and Walworth counties, while membership is available in Illinois to those who live or work in Winnebago County, the credit union said.

Then-$474 million First Community assumed the assets and liabilities of First American Credit Union of Beloit, Wis., when that $137 million credit union was liquidated in 2010. Operations at First American locations continued under that credit union’s name after its liquidation. Those locations will now carry the Advia name and branding.

In an FAQ section on its website, Advia said, “Our new name of Advia Credit Union was selected by our Board of Directors as a reflection of the value we provide our members: The ability to experience advantages via innovative financial solutions. In developing our new name, we worked to introduce one that identifies with our commitment to providing extraordinary service, as well as able to be trademarked as unique to us moving forward as we continue to grow into new communities.”