"Beltway here we come," Kris Young said in a Facebook post.
The trucks, adorned with American flags and posters, honked their horns and waved to supporters flanked along the roadways.
The "freedom" convoy started last week in California and sparked smaller ones around the US.
Truckers plan on taking the DC Beltway/I-495, circling it twice and then returning to Hagerstown.
Click here to track the group on Facebook.
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