The report, which surveyed 27 cities across the country, also said the demand for hunger assistance is up.
"We really have been baffled (as to) why so many families are falling into homelessness," said Deronda Metz, the director of Social Services for the Salvation Army Center of Hope. "Last year at this time, we were serving about 100, 120 children. This year, we're serving on average about 165 children a night."
Melinda Robinson, a resident of the shelter since September, lives there with her four children and said it is difficult to find enough space.
"It is so crowded, to the point where some people have to sleep in the TV room just to accommodate a lot of the families coming in," she said.
"Our resources are definitely overburdened," Metz said. "It's challenging."
According to the report, Charleston had the biggest increase in homeless families, with an 81 percent increase. Charlotte was second on the list and Portland was third at 31 percent.
The report also said demand for food assistance in Charlotte has increased by 21 percent. It said one of Charlotte's biggest challenges will be raising money to pay for more emergency food, and went on to say that city officials "expect requests for food assistance in the coming year to increase moderately, while resources to provide food assistance are expected to decrease moderately."
At Loaves and Fishes food pantry on Tuesday, volunteers were busy packing up carts with food. The pantry's spokesperson said they are on track to provide food for a record 110,000 people by the end of the year.
Charlotte city officials said they've created a task force called the Charlotte-Mecklenburg Coalition for Housing, which oversees a 10-year plan to end and prevent homelessness. The plan's goals include finding out what is causing homelessness to develop strategies to combat it; funding and helping to build affordable housing in Charlotte; and organizing funding to help people stay in their homes when they are in financial crisis.
Robinson said the resources are badly needed.
"Just the support of the other people that are here makes it a big difference," she said.
To see the full U.S. Conference of Mayors report, click here.