The billboard was purchased by the Utah Coalition of Reason with a $3,678 grant from the Washington D.C.-based United Coalition of Reason and will remain up through Sept. 19.
"We're hoping to reach a lot of people on their way to the Utah State Fair," Elaine Ball, director of the Utah coalition, said Tuesday. "We hope people will discover that we are a legitimate part of the community."
The 2-year-old coalition includes a number of older Utah organizations that question belief in a deity, according the website, www.reasonutah.org.
"We want everybody to know we're coming together as people who are atheists, agnostic or freethinking and open to discussing ideas," Ball said. "We're not trying to convert or de-convert people."
For his part, the Rev. John Williams, rector of St. James Episcopal Church in Midvale, finds the billboard inoffensive.
"For me, it seems pretty benign," he said. "As a statement of fact, I believe it. Those are the people we are trying to reach."
The Utah Coalition of Reason also seeks to act as a counterbalance to public discussions embracing religion and the blurring of lines between church and state, Ball explained.
"It's a concern that candidates embrace God publicly," she said. "We're in a political climate where it's not acceptable to embrace humanism. We'd like to change that."
Ball also said a strong emphasis on Christianity by politicians, including some Republican presidential aspirants, serves to alienate other Americans, including Muslims or Jews.
"It ought to be a cause of concern," she said, "for people of all beliefs and religions who don't identify with people like [Texas Gov.] Rick Perry."
But tossing religion about in the political arena is nothing new in the United States, said Matthew Burbank, University of Utah political scientist.
"It's not out of the norm of what we've [traditionally] seen," he said of the lead-up to the 2012 election. "George W. Bush in 2000 gave a number of speeches about his beliefs."
Still, Burbank said the billboard serves a purpose.
"Freedom of religion also means, I'm free not to choose any religion," he said. "It's useful to remind people of that, because it's part of the American experience."
Among other things, the Salt Lake City billboard is part of a national campaign that seeks to remove any social stigma for those who do not believe in a deity, according to Fred Edwords, director of the United Coalition of Reason.
Nonbelievers are "inundated with religious messages at every turn," he said. "We hope our effort will serve as a beacon and let them know they aren't alone."
Utah Coalition of Reason members
Humanists of Utah; Atheists of Utah; Salt Lake Valley Atheists; Atheists of Utah Valley; Dixie Reason Inquiry and Free Thought (Dixie State College); The Godless Horde of Salt Lake; Post Mormon; Salt Lake City Skeptics; Utah Freethought Society; Secular Humanism, Inquiry and Freethought (University of Utah); Secular Humanists, Atheists, and Free Thinkers (Utah State University); Secular Humanist, Atheist, Agnostic, Free Thought (Utah Valley University).