The Upper East Side is in deep spit.

A deranged woman has been spitting on residents and visitors for at least five years — and victims say police have told them to just turn the other cheek.

No one seems to know her correct name — although some have been referring to her as “Susan.’’

The woman has become infamous as “The Spitting Lady of 77th Street.’’

Neighbors even set up a Facebook page to report on the latest sightings — so readers can avoid the locations.

Two brothers — both of whom asked to remain anonymous — are among her recent would-be victims.

They say they avoid public spats with her by staying out of range when they pass her.

“She spits and attacks children walking down the street. Her victims are random: could be a baby in a stroller or an old man — it doesn’t matter, she’ll just spit and yell,’’ said one of them.

He added, “We’ve called the NYPD countless times and were told it’s out of their hands. Even [Mayor Bill] de Blasio won’t help do anything about it.’’

Everybody between 77th and 84th streets knows about her, he said.

The man’s brother said, “My son literally cannot walk in specific areas of the neighborhood because he’s terrified of her.

“Every time we run into her, she spits at us. One hundred percent chance she’ll do it.

“I can’t believe I have to take a cab like three blocks down the street to avoid her.”

James Cassidy, who also lives in the area, said of the woman, “Everyone around here knows her. Vile person, man. She just spits and yells at innocent bystanders for literally just walking past them.”

Erica Brennan, 41, said, “I refuse to walk my children around this area strictly because of the spitting lady. She’s always on 77th and Lex.

“The police won’t even help. It’s not fair.”

Susan Marra said, “I’ve lived in this neighborhood for almost 10 years and this woman has done nothing but give it a bad name.

“She curses, spits and harasses the people just trying to get by. I’ve notified the police numerous times — and they never showed up.’’

Anthony Ayala, who lives on Second Avenue, believes the spitter has a son.

“I see her walking with her son sometimes. Son’s a pretty big guy, which is probably why no one does anything about it.”