Text and photos by Alok Chowdhury

For all the wealth of the United States, homelessness remains an acute problem, with more than 643,000 people homeless on any given night, according to the National Alliance to End Homelessness.

Roughly a third of the homeless are families and two-thirds are individuals, the organization estimates, and about 17 percent are “chronically homeless.” Many of these people have serious psychological issues or substance abuse problems; many of them have been in treatment programs in the past yet remain homeless.

Military veterans are among the homeless. The Departments of Veterans Affairs (and Housing and Urban Development in a 2010 report to Congress estimated that 76,000 veterans experience homelessness on any given night. They include people who have served in conflicts starting with World War II, though research indicates that those serving in Vietnam and post-Vietnam eras are at greatest risk of homelessness. Veterans returning from Afghanistan and Iraq often have severe disabilities that are known to be correlated with homelessness. Homeless women veterans are more common than in the past.

In New York City, each night more than 45,000 people — including 17,000 children — experience homelessness, according to Coalition for the Homeless. At least 41,200 homeless men, women, and children bed down each night in municipal homeless shelters, and thousands more sleep on the streets or in other forms of rough shelter.

Here are some of them, identified by given names or nicknames only.