LOS ANGELES — Los Angeles County’s annual count of homeless residents began Tuesday night — a crucial part of the region’s efforts to confront the crisis of tens of thousands of people living on the streets.

Up to 6,000 volunteers with the Los Angeles Homeless Services Authority fanned out for the effort’s main component, the unsheltered street tally.

The so-called “point-in-time” count will take place over three days and aims to estimate how many people are unhoused and what services they may require, such as mental health or drug addiction treatment.

LA County’s undertaking is the largest among similar tallies in major cities nationwide. The tally, which also makes use of demographic surveys and shelter counts, is mandated by the federal government for cities to receive certain kinds of funding.

The count this year comes amid increasing public outrage over the perceived failure — despite costly efforts — to reduce the surging population of people living in cars, tents and makeshift street shelters.

The 2023 effort reported more than 75,500 people were homeless on any given night in LA County, a 9% rise from a year earlier. About 46,200 were within the city of Los Angeles, where public frustration has grown as tents have proliferated on sidewalks and in parks and other locations.

Since 2015, homelessness has increased by 70% in the county and 80% in the city.

Karen Bass, the mayor of Los Angeles, joined city and county officials to kick off the count Tuesday night in the North Hollywood neighborhood of LA’s San Fernando Valley.

The count “is an important tool to confront the homelessness crisis,” Bass said in a statement. “Homelessness is an emergency, and it will take all of us working together to confront this emergency.”

On her first day in office in Dec. 2022, Bass declared a state of emergency on homelessness. One year into her term, the mayor, a Democrat, announced that over 21,000 unhoused people were moved into leased hotels or other temporary shelter during 2023, a 28% increase from the prior year. Dozens of drug-plagued street encampments were cleared, and housing projects are in the pipeline, she said last month.

City Hall, the City Council and the LA County Board of Supervisors have said they intend to work together to tackle the crisis. Progress hasn’t always been apparent despite billions spent on programs to curb homelessness.

Homelessness remains hugely visible throughout California with people living in tents and cars and sleeping outdoors on sidewalks and under highway overpasses.

The results of the LA County homeless count are expected to be released in late spring or early summer.