Parkgoers say drug use has surged at some of the city’s most popular parks — at the same time drug arrests have plummeted.

“Drugs are a huge problem in the park recently,” said mom Mary McGraw of Washington Square Park in the Village, where she takes daily strolls with her 11-year-old son. “In my 17 years in New York City I’ve never seen it the way it is now, and some of those dudes are scary.”

Park regular Steven Hill said he witnesses “pills being sold” by brazen dealers.

“The person selling them drops them on the ground, then the person buying them picks them up. It happens a lot in the bathroom,” he said.

A gathering spot near the park’s western border near MacDougal Street has become known as a “drug corner,” where pills and pot are bought, sold and used.

“I’ve seen people going crazy running up and down the street,” McGraw said. “I see them jumping up and down out of their minds.”

Residents of Washington Place formed the “Save Our Street” block association in September in response to the drug surge.

“It’s just a continuous loop of people sitting on those steps and smoking crack,” said Nancy Bass Wyden, the owner of the nearby Strand Book Store and co-organizer of “Save Our Street.”

A second community group also declared, “We will no longer tolerate the illegal mostly drug-related activity within Washington Square Park and the immediate Greenwich Village neighboring areas,” Washington Square Park 4 Us All wrote in a Nov. 1 email blast to park patrons, urging them to reach out to elected officials about the issue.

While complaints are rampant, arrests are rare.

Cops made 56 drug-related arrests in the park this year through Oct. 6, an average of 1.4 per week, according to the NYPD. Arrests averaged 1.2 per week in 2018 (an annual total of 66) and 1.5 per week (77 for the year) in 2017 — the last full year before Mayor Bill de Blasio ordered Finest to stop cuffing pot-smokers.

In Riverside Park on the Upper West Side, Carin Gilfry said her 2-year-old daughter found tiny, brightly colored vial caps that appeared to be coated in drug residue. They resemble pieces of a child’s toy.

“Luckily, I grabbed them from her before she could put them in her mouth,” Gilfry recalled. “You can overdose on a few grains of fentanyl. If that was fentanyl, my kid could be dead.”

Cops nabbed 20 people for drugs in the 267-acre park through Oct. 15 of this year — an average of 0.48 arrests per week. Arrests totaled 48 in 2018, with a weekly average of 0.92, and 174 in 2017, an average of 3.3 per week.

The trend extends to parks across the five boroughs, NYPD stats show.

At Cadman Plaza Park in Brooklyn, the NYPD hasn’t arrested anyone for drugs in the past three years, the department said.

Kids found syringes discarded under bushes there on Aug. 25, and park workers discovered used needles stowed in rat holes the next day, the Brooklyn Eagle reported.

“I find it disgusting. It’s right across from the federal court building … You would think that they would have more security over here,” fumed Fort Greene’s Angeleck Butler, as she strolled through the park with her 4-year-old niece.

At another green space with a known drug problem, Tompkinsville Park on Staten Island — the backdrop to Eric Garner’s fatal 2014 arrest — the NYPD has collared 10 people for drugs in the past three years, as of Oct. 20.

“I see kids playing in the park, and they are exposed to drugs and paraphernalia,” said Shema, a parkgoer who declined to provide her last name. “I see cops all the time, but they don’t seem to be doing anything.”

At Tremont Park in the Bronx — among more than a dozen NYC green spaces where city officials installed syringe-disposal kiosks last year — teenage parkgoers told The Post they watch their step to avoid stomping on a used syringe.

“This park is not safe. Especially the back side. People do heroin all around the edges of the park, in the middle of the day, and you see the needles and empty bags everywhere,” said 16-year-old Stephen, who also declined to provide his last name. “They have these garbage can things for people to put their needles in, but I guess they don’t use them. The s–t is crazy.”

Police arrested eight people for drugs in Tremont Park between Jan. 1, 2017, and Oct. 20 of this year, the department said.

“I see a lot of needles, everyday, everywhere. Drug dealers and meth heads are here, 24-7. I see a lot of cops here. The 42nd precinct is right around here, but I’ve never seen them arrest anybody,” said Chris Garcia, 19.

“I worry about my dog. I don’t want him to step on a needle or eat a needle.”

The NYPD “adjusts deployments regularly [in the parks] based on real time crime and conditions,” Sgt. Mary Frances O’Donnell said, noting its “Neighborhood Policing philosophy has allowed our police officers to strengthen the bonds with the communities we serve and by working together, the NYPD is able to gather information, solve crimes and keep people safe.”