Nonreligious organizations will gather on the steps of the Lincoln Memorial Saturday in Washington in an effort to show they are a voting bloc to be reckoned with come November.
Reason Rally 2016 organizers said they expect about 30,000 people to attend the event, which will be held from 10 a.m. to 7 p.m.
Lyz Liddell, executive director of the Reason Rally Coalition, told CNN the rally is "absolutely" a political event.
"That's the reason we're holding this in an election year," Liddell told the news organization. "We want to see reason taking precedence over religious-driven ideology."
A similar event was held in 2012, which was also an election year, but she said the atmosphere surrounding it may have seemed more exclusionary.
"Some of our speakers were anti-theists and anti-religion," she told CNN, saying the focus of this year's rally is more secular. "We need to ally with people who share our goals. It's not an 'atheist vs religious people' conversation."
FILE - People gather for the Reason Rally on the National Mall March 24, 2012 in Washington, DC. Atheists and those who oppose religion in government gathered for a rally where they celebrated not having religious affiliations.
Reason Rally's website says those expected to attend include secular, atheist, agnostic, humanist, freethinking and nonreligious people.
The dozens of speakers planned for Saturday's event include "science guy" Bill Nye, comedian Julia Sweeney, magician Penn Jillette, Representative Tulsi Gabbard of Hawaii and NASA scientist Carolyn Porco.
Speakers will address science-based sex education in schools, transgender people's use of public restrooms, and evidence-based responses to climate change, Liddell told U.S. News & World Report.
Ahead of Saturday's Reason Rally, the Pew Research Center said it's hard to estimate the number of atheists in the United States.
The matter is complicated, researchers said, because some adults who describe themselves as atheists also say they believe in God or a universal spirit. Meanwhile, some people who identify with a religion, such as Catholicism or Judaism, say they do not believe in God.
Some Pew findings about atheists:
- A 2014 religious study found that 3.1 percent of American adults say they are atheist, someone who believes God does not exist, up from 1.6 percent in 2007.
- Four percent of Americans say they are agnostic, someone who claims neither a faith nor a belief in God, up from 2.4 percent in 2007.
- Overall, 23 percent of Americans say they have no religious affiliation, according to the poll.
- In general, most atheists are male (68 percent) and likely to be younger (34 years old) than the overall population.
- About a third of atheists say they look primarily to science for guidance on questions of right and wrong, up from 20 percent in 2007.
- Politically, 51 percent of Americans said they would be less likely to support an atheist candidate for president, the 2014 poll found. It also found that 53 percent of Americans say it is not necessary to believe in God to be moral, while 45 percent say belief in God is necessary to have good values.