The planned protests will begin on Saturday morning, local time.
Among other things, profiles within the radical right and conspiracy theorists will participate in the protests, reports the Washington Post.
Counter-demonstrations are planned to be held nearby.
The protesters are supported by, among others, the chairman of the group Proud boys, which is classified as right-wing extremist by the FBI, writes Washington Post.
Infowars founder and conspiracy theorist Alex Jones has also announced that he will take part in this weekend's demonstrations.
Several demonstrations
According to experts on right-wing extremism that the local newspaper The Washingtonian has spoken to, there is a high risk of conflicts arising between Trump supporters and counter-protesters, and there is a risk that the demonstrations will be violent.
The police have received information about the demonstrations and state that they have also marked out places that will be closed in the meantime.
Neither the police nor other responsible authorities have given any permission for the total of three different demonstrations against the election result and to support Donald Trump.
However, an application for a permit is being reviewed by the authorities, according to the Washington Post.
Trump: "Maybe come by"
Washington police have warned to bring weapons to the demonstrations.
- We see how some communicate in a way on social media that indicates that they will bring firearms here, says Peter Newsham, police chief in Washington to NBC and adds that in that case it is a crime in the District of Columbia.
On Friday, Donald Trump wrote on Twitter that he will possibly visit the demonstrations himself.
"It's heartwarming to see the enormous support out there, especially the demonstrations that are spreading organically across the country, including a large demonstration in Washington on Saturday.
I might even come by and say hello ", he writes on Twitter.