Homeless congregate in cities because density improves economies of scale. More shelters per square mile which is important if they fill up fast, more foot traf

Homeless congregate in cities because density improves economies of scale. More shelters per square mile which is important if they fill up fast, more foot traffic for pan handling, more industrial/business areas where they are less likely to be harassed by police, more nooks and cranies to hide from the elements, more homeless people to group up with for safety, and so on. The vast majority of reasons that homeless people stay in urban areas is the failure of the surrounding areas in providing for their basic survival.