The Catholic Church in North Georgia is now the 26th largest diocese in the country, falling between El Paso, Texas, and Providence, R.I.

The Atlanta Archdiocese recently updated its official Catholic population figure, nearly doubling in size to 650,000 from 350,000.

Leaders said the new headcount better reflects reality as the church comes to grips with its 10 years of explosive growth. The new population number for the first time counts people not in the habit of registering as parishioners either for cultural reasons or out of concerns the registry might be used as a tool for immigration enforcement.

Msgr. Luis Zarama, vicar general, said the population figure now recognizes people who were missed in the past.

“The 350,000 never reflected the Hispanic community. We cannot ignore half of our people,” he said.

The census in the 2006 Official Catholic Directory positioned Atlanta in 55th place as a diocese.

The robust number shows how the Catholic Church is growing in the Southeast, where Catholics have not traditionally been a large church community. The region is drawing transplants from the Northeast and other parts of the country, while newcomers from Vietnam, Korea, Mexico, Colombia and Nigeria are also filling the pews.

Consultant Peter Faletti said the church community over the last decade has become much more international.

“In the last 10 years, the ethnic mix of the archdiocese has continued to change,” he said.

Parishes are adapting with new services. St. Thomas the Apostle Church in Smyrna celebrates nine Masses each weekend, five in English and four in Spanish. Other churches hold Masses in foreign languages such as Igbo for Nigerian Catholics.

“It’s a very dynamic archdiocese. It’s a definite challenge how we can serve the growing needs of our people,” said Msgr. Zarama. “What we have in Atlanta reflects the Catholic Church. Catholic means universal. That will enrich us.”

Indeed, the number of parishes has to keep growing to keep up with the worshippers. The archdiocese now has 84 parishes, up from 77 in 2002. In 2006, Archbishop Wilton D. Gregory blessed two more parishes.

The Archdiocesan Planning Committee released the new figures as it works on long-term goals for future facilities and services.

How did the number change? Leaders in the church decided to change how to count worshippers. In the old system, parishes reported only the number of registered people on the books. The new figure reflects registered parishioners, along with a best estimate from pastors on who is showing up at Mass but not on the books.

“In many, many parishes, the unregistered (parishioners) equaled registered,” said Faletti, a consultant from the North Highland Co. who is working with the archdiocese as part of the planning process.

A researcher said the church may actually be undercounting the number of Catholics.

Clifford Grammich, of the Glenmary Research Center in Cincinnati, which monitors religious membership around the country, said surveys and other statistics show the Catholic population in North Georgia could be as high as 800,000 people.

Three factors drive the increase. One is the arrival of Catholics from the Northeast and the Midwest. Catholics make up some 25 percent of the nation’s population, but about 10 percent or less in the South.

“Migration from comparatively more Catholic regions to Georgia should continue to boost the Catholic population,” Grammich said in an e-mail.

Secondly, Georgia’s immigrant population has boomed in recent years drawn to the healthy business climate and Atlanta’s role as an international gateway. The U.S. Census Bureau estimates that more than 30,000 immigrants each year are settling in North Georgia, Grammich said.

Recent surveys have shown the new immigrants are at least 40 percent Catholic, which means the immigrant population likely added about 60,000 Catholics to the mix in the last five years, he said.

But perhaps the biggest factor is the impact of the influx of predominantly Catholic Hispanics to metro Atlanta.

The Hispanic population growth alone has added more than 160,000 Catholics in recent years, Grammich said. And this influx of people may mean Hispanics are a majority, or near majority, of Catholics in North Georgia, he said.

The old system of relying on registered parishioners to do an accurate survey does not work with the many international Catholics.

Msgr. Zarama said the new arrivals come from church cultures where people do not sign up to be a member of the church. The new people moved from countries where Catholics predominate so the idea of church membership is much different, or they lived in small towns where people knew everyone in the church, Msgr. Zarama said.

Also, the state has drawn illegal immigrants, as many as 450,000, according to the Pew Hispanic Center, a Washington, D.C., think-tank.

Msgr. Zarama said fears about immigration enforcement also dissuade illegal workers from signing up at parishes. He said people believe church records could somehow hurt them so they do not put their name on the parish rolls. In fact, church records are not used for any immigration-related matters.