The group behind these marches is ACT for America, the largest anti-Muslim group, in the United States, which has been listed as a hate group by the Southern Poverty Law Center.
In Austin, dozens of anti-Sharia protesters carried American flags and signs claiming that Islam "enslaves women" and is a "death cult".
In many cities, the ACT protestors were outnumbered by counter protestors who said the protests were fueling racism and anti-Islamic hatred. If they tell you it's about free speech, they're liars. "America as we all know is a country of immigrants, its built on diversity". Tensions rose when counter-protesters crossed the street to meet the anti-Sharia group, tossing jugs of rotten milk across the barrier that separated them.
Counter-protesters in Syracuse responded by shouting "Shame!"
Opponents of anti-Muslim demonstrations said the events stoked unfounded fears and a distorted view of Islam. If you feel unsafe "walking around in a hijab, try being a conservative on a college campus", Pax Hart, who organized the NY march, said. They don't want us in their country.
"All across this country today, people came out and shut the racists down", said John Beacham of Answer Chicago. Soon, dozens of anti-Sharia law activists started their own rally across the street, protesting what they say are certain aspects of the religious law forming part of the Islamic tradition.
Hundreds of counter-protesters marched through downtown Seattle, banging drums, cymbals and cowbells behind a large sign saying "Seattle stands with our Muslim neighbors".More news: Death toll from Pakistan attacks climbs to 73
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After scuffles broke out between the groups, State Troopers arrested seven people for disorderly conduct and obstructing the legal process.
At least 20 people including a Republican candidate for Georgia governor gathered in an Atlanta park for a protest against Islamic law. Three times as many counter-protesters demonstrated outside.
In St. Paul, Minnesota, the demonstrations were mostly peaceful until some people leaving a rally inside the Capitol encountered counter-protesters outside.
The anti-Muslim protesters were met by counter-protesters who denounced their rhetoric as demeaning and insensitive. The marches were organised by ACT (American Congress for Truth) for America, which describes itself as a "grassroots national security organization" that vows to defend America's founding "western values" and "protect America from terrorism".
While many Muslims liken Shariah to other religions' laws that guide the faithful but don't supercede the rules of secular societies in which they may live, some states have been concerned enough to pass legislation prohibiting the use of foreign law in state courts.
ACT claims that it does not hate Muslims and disavowed a volunteer organizer in Arkansas who was affiliated with white supremacist groups.
The Council on American-Islamic Relations in May said that the number of anti-Muslim incidents surged 57 percent last year compared to the year 2015.
The SPLC says Oath Keepers is "one of the largest radical antigovernment groups in the United States", organised around a "set of baseless conspiracy theories". Anti-Muslim hate crimes soared in London after the terrorist attack earlier this month.