In a Brit context, homeless encompasses both rough sleeping and sofa surfing.

There's countless homeless who aren't sleeping rough on the streets but are taking space, unofficially in someone's spare room, or literally on their sofa or floor. How are the two forms of homelessness distinguished in US usage?

Rough sleeping is as it suggests: Sleeping outside, sleeping bag in shop doorway, tent, abandoned building, under the railway bridge etc.

“Homeless” includes people who are housed in dormitories, or who have to sleep on a friend’s sofa.

“Rough sleeping” largely means sleeping outside, or “on the street”.

The rough sleeping set is a subset of the homeless set.

Same here, I didn't fully grasp the meaning from the article. Despite some of the skeptics' comments here, what I find fascinating is that we have a subject that could include a variety of situations (poor and living on the street, poor and sleeping on someone's couch, middle income and voluntarily choosing not to have a permanent living place), yet we tend to throw it all into the same "homeless" bucket.

Another commenter suggested that "unsheltered" is the American equivalent to rough sleeping, and I think that makes a lot of sense, even though I haven't heard it much.

Homelessness is obviously an issue in many American cities, and perhaps using more specific definitions could help us understand the issues unique to each group.