Falsehoods about election interference are swirling online, stoking calls for violence on Election Day. The rumors touch on everything from ballot boxes to how the “deep state” — a so-called secret cabal of elites — is involved.

The misinformation is worrying researchers who track such content, and who said the volume of lies online had soared. Some of the individual lies are shared only dozens or hundreds of times each, but added together they have attracted millions of likes and shares across social media and are inflaming an already tense electorate, the researchers said.

Election-related misinformation has “been building up virality, using Facebook pages and groups as fertile ground,” said Fadi Quran, a campaign director at Avaaz, a progressive human rights nonprofit that studied some of the rumors.

Here is a sampling of some of the falsehoods making the rounds online ahead of Election Day.

A Democrat-led Coup

The baseless idea of a Democrat-led coup against President Trump has gained the most traction among election-related rumors about violence, according to Avaaz. A New York Times analysis found at least 938 Facebook groups, 279 Facebook pages, 33 YouTube videos and hundreds of tweets spreading the falsehood, mostly in right-wing circles.

On Sept. 14, Dan Bongino, a popular right-wing commentator and radio host, posted a Facebook video pushing the rumor. It was viewed 2.9 million times.

In a text message, Mr. Bongino said the idea of a Democratic coup was “not a rumor” and that he was busy “exposing LIBERAL violence.”

Blocked Ballots

Some election-related lies are also circulating among left-wing groups. For instance, a left-wing Facebook page called The Other 98% posted in August that mailboxes were being blocked by unknown actors to effectively discourage people from voting. The post with the false claim collected 39,000 likes and comments on the social network and reached 18 million people, according to CrowdTangle, a Facebook-owned tool for analyzing social media.

In total, voting-by-mail rumors have topped election misinformation this year, according to a September analysis by the media insights company Zignal Labs. Nearly a fourth of all the mentions last month about voting by mail on television, in print and in online news — or 3.1 million mentions — amounted to misinformation, Zignal Labs found.

The Covid ‘Scamdemic’

Another election falsehood spreading on Facebook is the notion that an elite cabal, or “deep state,” was interfering with the vote by inventing the coronavirus pandemic.

One post from August that got 795 likes and comments on Facebook was a meme with the caption, “The Covid scamdemic was devised by the Deep State to promote the use of ballots by mail. This is the way the Democrats can create massive election fraud.”

This lie is representative of how the “deep state” is portrayed online as responsible for all sorts of ills against President Trump. In another rumor, the deep state is bent on destroying ballots voting for Mr. Trump. And the deep state is also represented online as being intent on falsifying votes in favor of Mr. Trump’s Democratic opponent, Joseph R. Biden Jr.

A ‘Civil War’ on Election Day

Another widespread rumor is that a “civil war” is being planned and will erupt on Election Day. The baseless idea is showing up on sites like that of Glenn Beck, the former Fox News host and conspiracy theorist, according to a Times analysis. Mr. Beck’s Facebook page, which has three million followers, has also pushed the rumor.

Mr. Beck did not immediately respond to a request for comment.

“If Trump wins the election BLM and antifa are going to burn this country down,” said another post on a pro-gun Facebook page, referring to the Black Lives Matter racial justice protesters and antifa, a loose collective of far-left activists. “If Biden wins they come for your freedom and your guns. Either way a War is coming. Are you ready?”

The posts about a looming civil war aim to create an atmosphere of fear so that voters are deterred from voting on Election Day, misinformation experts said.