Placer County’s homeless population decreased slightly compared to the previous year, according to county results from the annual point-in-time count published by the Homeless Resource Council of the Sierras.

A total of 584 homeless individuals were counted across the county, from Roseville to North Lake Tahoe. The count surveyed unsheltered and sheltered individuals. It was conducted by volunteers and county staff on the night of Jan. 24. By comparison, 663 homeless individuals were identified in the 2017 count.

Of adults who responded to detailed survey questions, 39 percent were chronically homeless, 41 percent reported having a serious mental illness, and 23 percent had a substance use disorder.

Point-in-time counts are not a comprehensive measure of an area’s homeless population, but rather snapshots from a single day that can be used to approximate broad trends. Officials say they are viewed as undercounts for a community’s yearly overall homeless population because many people may move in and out of homelessness throughout the year.