Ellis, a computer programmer, is not the only one delighted by the thought of bringing more atheists to the state.
Potential speakers initially hesitated to attend the convention until he told them the location. Then they eagerly committed, he said. "Meeting in Zion, in the heart of Mormonism, will, no doubt, bring a large showing."
The group will be "shining a spotlight on the LDS Church to highlight the fact that it is an oppressive organization that wields too much power in Utah and surrounding states," Ellis wrote in an email. "Mormons raised more than $20 million in support of the homophobic and hate-driven Proposition 8 in California that denied the civil right of marriage equality to the LGBTQ community."
The battle between the two groups also played out during the 2012 presidential campaign.
American Atheists tried to rent billboard space for a sign mocking Mormonism, the faith of then Republican nominee Mitt Romney, saying: "God is a Space Alien, Baptizes Dead People, Big Money, Big Bigotry." The words were accompanied by a man in white underwear, alluding to Mormons' sacred temple undergarments.
The billboard's kicker said in bold letters "Atheism: Simply Reasonable."
This year's American Atheists' convention just wrapped up in Austin, Texas, 50 years after the group was launched there.
It started in 1963 after famed nonbeliever Madalyn Murray O'Hair won her case before the U.S. Supreme Court, ending prayer in the nation's pubic schools.
"American Atheists is dedicated to working for the civil rights of atheists," its mission statement proclaims, "promoting separation of state and church, and providing information about atheism."
The national organization last met in Utah in 1984, nearly 30 years ago, Ellis said. Since then, its numbers, activities and influence have increased.
With 150 or so paid members, the Utah chapter now sponsors weekly coffee chats in Salt Lake City and Ogden, quarterly parties on each solstice, and an annual gala. Members also march in the Pride parade and have adopted a section of State Street in Utah's capital.
"We provide a lot of the same social services people had previously found in their religious organizations," Ellis said in an interview.
With the help of his six-member board, Ellis will be logging lots of hours getting ready for the big event next year, but he says it will be worth it.
"We're sure," he said, "it is going to be the largest and most successful convention yet."
Coming to Utah
American Atheists will stage its national convention on Easter weekend, April 17-20, 2014, in Salt Lake City.