Prince William County’s emergency winter shelter for the homeless opened last week, at a time when the county has the D.C. area’s highest rate of unsheltered homeless, according to an annual study.

The 2011 Count of Homeless Persons published in May by the Metropolitan Washington Council of Governments found that 46 percent of homeless people in Prince William County are “unsheltered.” That is by far the highest percentage among the nine Washington-area jurisdictions that receive federal Continuum of Care grants. Arlington County had the second highest rate, with 30 percent of the homeless population being unsheltered.

Prince William County also experienced the most growth in its homeless population from 2010 to 2011. The number of homeless in the county grew from 488 in 2010 to 675 in 2011, a 38 percent increase.

The MWCOG study found that the increase in Prince William County was due to the higher number of families experiencing homelessness: 142, up from 100 families in 2010. The study’s authors said that the national economy was a large factor, as well as the exhaustion of federal Homelessness Prevention and Rapid Re-housing funds.

Families who “timed out” of HPRP funds found it more difficult to keep paying rent, the study found, meaning that more families were forced into homelessness. The study also noted that 230 families currently receive HPRP funds from the county, and when those funds expire, the homelessness situation could worsen.

Prince William County had more homeless families than any regional jurisdiction except for the District of Columbia and Fairfax County, according to the report.

Some other key points from the study:

• The county had 87 single adults who met criteria to be considered “chronically homeless,” and 11 families were chronically homeless. That is more chronically homeless families than any other jurisdiction except for D.C.
• Of the 11 chronically homeless families in Prince William County, eight were unsheltered. No other jurisdiction in the region had unsheltered chronically homeless families.
• The number of homeless single adults dropped 27 percent from 2007 to 2011, but the number of homeless people in families rose 34 percent.
• Nearly half (45 percent) of homeless adults in families in Prince William County were employed (compared to 38 percent regionally). Only 20 percent of homeless single adults were employed, matching the regional average.
• The largest “subpopulations” of homeless in Prince William County: chronic substance abuse (47), domestic violence victim (40), military veterans (40), mental illness (33), physical disability (21).
• Nine homeless adults were “dually diagnosed” with substance abuse and mental illness.

The report has been prepared annually since 2001. It is based on a one-day count of the homeless population in each of the nine jurisdictions in the Washington, D.C. region that receive federal Continuum of Care funds. The data for Prince William County include the cities of Manassas and Manassas Park.

The report defines the homeless as "People who reside in some form of emergency or transitional shelters, domestic violence shelters, runaway youth shelters, and places not meant for human habitation, which include streets, parks, alleys, abandoned buildings, and stairways."

The 2011 count was conducted on January 26. The next count of the homeless population will take place in January, 2012.