I don't know where the homeless encampments are, but I've been going to DC for work every 6 months for the past 3 years and have not seen any homeless. Last time there I took a very long evening walk from the Lincoln Memorial to Congress and then back to through the Penn Quarter all the way to Kennedy Center, late in the evening, all prime tourist areas, and didn't see a single homeless person.

I'm sure they exist somewhere -- but downtown DC is definitely not "covered" with homeless encampments.