Waving American flags and carrying homemade signs, thousands of people took part in a “No Kings Day” protest Saturday at the Idaho State Capitol.

BOISE, Idaho — The 'No Kings' Protest is a nationwide movement with rallies happening all over the country, including Idaho. Thousands of people gathered in downtown Boise to display their frustrations aimed at President Donald Trump. I spoke with protesters and found they have a variety of different grievances against the current administration.

Organizers of the “No Kings” demonstrations said millions had marched in hundreds of events. In Oregon, tens of thousands of people gathered in downtown Portland for two large protests -- one that began in Tom McCall Waterfront Park and the other at the Oregon Convention Center.

Around 2,000 protests were planned on Saturday in opposition to President Donald Trump. Large crowds turned out in cities like Portland, Denver, Chicago, Houston and Los Angeles – and in smaller communities in traditionally conservative areas.

Hours after the Boise rally brought thousands to the Idaho State Capitol, Nampa’s own “No Kings” rally brought hundreds of the city’s residents to Nampa City Hall.

Organizers are calling for Americans to attend demonstrations across the country to protest President Trump on his 79th birthday.

NBC News' Jacob Soboroff reports from Los Angeles City Hall where thousands of protesters have gathered for a 'No Kings' protest against the Trump administration and ahead of the president's Washington D.