Organizers planned the rallies on Saturday at more than 2,600 locations, more than the figure from previous such protests in June.
At the rallies, participants accused the government of sidelining Congress and taking too harsh a stance on immigration.
In Washington, protesters gathered near the Capitol. People held placards expressing the need to defend democracy and reject dictatorship.
A man at the rally called on lawmakers to stand up and stop the president from taking more power than he is allowed.
A woman said it is scary to think of what the US is going to look like in the future. She expressed concern about whether her children will have the same level of freedoms that people have today.
The demonstrations also took place in Chicago, Illinois, where many people marched in protest of strict immigration policies and the move to deploy National Guard troops on the grounds of restoring order.
So far, there have been no reports of major turmoil at protests.
