The Los Angeles County Board of Supervisors have proclaimed today as “Everyone In Day,’’ to recognize the start of a United Way-led program aimed at shifting residents’ attitudes about allowing housing for the homeless in their neighborhoods.

With the number of homeless people growing dramatically and with sprawling street encampments cropping up under overpasses, on hillsides and along neighborhood sidewalks, the problem has commanded more dollars and more attention.

Supervisor Mark Ridley-Thomas reminded the audience at the board’s meeting that Wednesday is the one-year anniversary of voters approving Measure H, a quarter-cent sales tax to fund services for the homeless.

Measure H is expected to raise $355 million annually to fight homelessness. The city of Los Angeles has another $1.2 billion in bond funding for housing construction from its own Measure HHH. But money isn’t the only obstacle to addressing the crisis.

“The question of homelessness is not going away without a fight,’’ Ridley-Thomas said, describing Everyone In as a 10-year campaign “to harness the energies of Measure H and nurture the public will, so that community residents can be a part of a comprehensive set of solutions to confront the homeless crisis.’’

There are 57,794 homeless individuals countywide, based on the last published count in 2017. And more than two-thirds of voters backed both Measure H and HHH, leaving officials to believe they had a political mandate to build more housing.

But many proposed projects have encountered fierce resistance, from residents in communities ranging from Boyle Heights to Venice and from Temple City to San Pedro.

Herb Hatanaka of Special Services for Groups, a nonprofit organization that provides services to mentally ill homeless individuals, told the board that neighbors turned out in force to oppose one SSG project.

“(We were) stunned by the intensity of the opposition to anything homeless and anything mentally ill,’’ Hatanaka said.

Hatanaka said the project was in La Puente, but Supervisor Hilda Solis later corrected him, saying it was in the unincorporated area of Avocado Heights.

Backers of the Everyone In campaign, which includes business owners, labor leaders, community groups and nonprofit organizations, hope to change those attitudes through education and outreach.

“There’s a lot of talk about NIMBYs (not in my backyard) but we want to start talking about YIMBYs (yes, in my backyard),’’ Supervisor Sheila Kuehl said. “Everyone In means we’re all responsible for this.’’

Elise Buik, president and CEO of the United Way of Greater Los Angeles, cited a recent survey of Los Angeles residents with 70 percent of those polled saying they would support housing for the homeless in their neighborhood.

“So that’s what this campaign on Friday will seek to do, is to activate residents all throughout the county and neighborhoods all throughout the county to be part of the solution,’’ Buik told the board.

Solis said she has talked to city officials who don’t want to apply for planning grants related to homelessness, while residents oppose mobile showers for the homeless in their communities.

“My heart gets broken,’’ Solis said, saying more needs to be done to educate residents and community leaders.

The county’s goal is to help 45,000 people escape homelessness over five years and prevent another 30,000 from becoming homeless using Measure H funds.

Since last July, county outreach teams have connected with 7,500 individuals living on the street and been able to connect 3,000 people to services, according to Ridley-Thomas.

A total of 3,350 homeless families and individuals have been moved into permanent housing with Measure H funding, according to Phil Ansell, who heads the county’s homeless initiative.

The county recently approved nine projects that would add more than 400 units of housing for homeless individuals, and the city of Los Angeles has been averaging a production rate of approximately 300 units per year in recent years, according to the Planning Department report.

However, a recent report by the Los Angeles Homeless Services Authority estimated that the county has less than half the number of permanent supportive housing units it needs for homeless individuals, falling more than 22,000 units short.