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The horseman of Central Park stopped on a grassy plateau to survey the terrain, from the North Meadow to his left, the Great Lawn ahead and Strawberry Fields due south.

As cyclists and joggers plied the winding park drives, a nonstop stream of tourists approached the hard-to-miss horseman. They sought directions or a photograph of him and Trooper, his stately horse.

The horseman’s name is Detective John Reilly and for the past decade he and Trooper have had the rare distinction of being the New York Police Department’s only mounted team dedicated to patrolling Central Park.

“When people ask me, ‘How come you don’t have a partner?’ I say, ‘I do — he’s right here,’” he said, gesturing toward Trooper and the oversize police shield strapped to his broad chest.

But their days of patrolling the urban range are ending.

Detective Reilly is retiring this week — and not by choice. On Thursday, he turns 63, the department’s mandatory retirement age.

Trooper, 15, is also being put out to pasture, having logged 10 years on patrol, the typical limit for a city police horse.

Many officers leave the job after 20 years, when they become eligible for a pension. Very few stay long enough to “age out” — department parlance for hitting 63.

But Detective Reilly has always wanted to keep working, especially in recent years with a job that is literally a walk in the park as a “10-foot cop,” as mounted officers are sometimes called. (And one that has not required the detective to make many arrests or ever draw his gun.)

“I love it,” he said. “Where else can you get paid to ride a horse in Central Park?”

And so, he and Trooper have patrolled the park year-round Sunday through Thursday, rain or shine, for up to six hours a day.

“He’s put up with my singing and my bad jokes,” Detective Reilly said of Trooper.

No singular officer, or horse, will replace them, said Deputy Inspector Barry Gelbman, commander of the department’s mounted unit. Instead, the Central Park spot will likely be shared among several mounted officers, he said, so the odds are slim that another mounted officer will replicate Detective Reilly’s decade-long run.

In his 34 years with the department, Detective Reilly has become one of its most visible members, mostly because of his last 24 years with its mounted unit, an unusually long tenure.

Trooper, who is part Belgian, part quarter horse, was Detective Reilly’s favorite and longest-running of the six department horses he was paired with over the years, he said.

He even inquired about adopting Trooper.

“I’d like to keep him myself,” he said, before conceding that, living in an apartment in Glendale, Queens, he is really not in a position to own a horse.

He is comforted by the knowledge that the department’s police horses are treated well, receiving lifelong care on farms outside the city, where police officials are welcome to check on them.

The detective has been so reluctant to retire that he had to be reminded repeatedly by his boss to file the required paperwork.

“He’s fighting the inevitable to the last minute,” Deputy Inspector Gelbman said. “Him and the horse, they’re both creatures of habit.”

“It’s an emotional time,” Inspector Gelbman added. “He loves being a mounted cop and he connects to people on a personal level. It’s something he enjoys doing, to the point of, ‘I don’t want to leave.’”

While an enviable assignment, the detail can get dicey in bad weather, when even the middle of Manhattan can take on a high lonesome feel. Once, in a torrential downpour, Detective Reilly slipped clean off Trooper.

Largely, the mounted officer’s role in the park is to be a visible presence, to deter crime and to offer a friendly face. He also would relay calls to other officers in cars or on scooters, as in the case of a man who had exposed himself to people lounging on the Great Lawn.

“Our presence alone prevents crime and makes people feel safer,” he said, clip-clopping through the park the other day. “People can see you from far away and are less likely to commit a crime.’’

This, in a nutshell, is largely the role of the department’s mounted unit, which patrols large gatherings and crowded areas of the city. Formed in 1858, it has 55 horses and 100 members, split between officers and civilian workers.

Detective Reilly grew up in Jamaica, Queens, the second of eight children, and went from Jamaica High School to the Army, where he was stationed in Germany.

Shortly after joining the department in 1985, he was assigned to the 44th Precinct in the Bronx. He worked the overnight shift for nine years in one of the roughest parts of a city plagued with much higher crime levels than today.

The radical shift from that detail to his more placid Central Park post partly parallels the city’s decline in crime and its soaring tourism, especially in Central Park.

“Even in my 10 years here, the increase in the volume of tourists is just unreal,” said the detective, who often wears a cowboy hat while commuting by subway from Queens to the unit’s Manhattan headquarters on the ground floor of Mercedes House, a luxury residential building on West 53rd Street that houses a Mercedes dealership next to the stable.

While saddling up Trooper, Detective Reilly slipped him his favorite treat, jelly beans.

“The other horses hate that he gets this stuff,” he said as he laid a blue police department blanket on Trooper’s back and then an English saddle equipped with an old-fashioned night stick.

Then he put on his cavalry-style uniform, with a heavy leather coat, his blue police helmet and his 9-millimeter pistol, and rode Trooper to Central Park along their daily route.

Heading along a busy stretch of West End Avenue, the horse passed double-parked cars, aromatic food trucks, dumpsters and garbage trucks without reacting. Even a construction crew jackhammering the street failed to break his stride.

“Some horses would go bananas at that,” said the detective before entering the park and stopping on a rise so that Trooper could graze.

“He loves Central Park grass,” said Detective Reilly, who knows many of the bird watchers and dog walkers in the park and always asks tourists where they are from.

When two tourists from Ottawa told him it was their first visit to Central Park, he pointed out Tanner’s Spring, a fresh spring just west of the Great Lawn.

Two mounted officers with the city’s Parks Department, which also patrols the park, approached and said they heard he was retiring.

“Are you excited?” one asked.

Detective Reilly shrugged, and finally said tersely, “I’ll miss it.”

Then the horseman of Central Park prodded his equine pal into his daily run, a full gallop down a park pathway with the detective whooping with joy.