GORDON, Wis. — “Welcome’’ to hell.

Exclusive Post photos offer a chilling look inside the ramshackle Wisconsin cabin where accused kidnapper Jake Patterson allegedly held 13-year-old Jayme Closs prisoner for 88 days after killing her parents.

Visitors are greeted by a battered sign above the home’s front door that reads “Patterson’s Retreat” and another that says “Welcome.” But the grounds, which are littered with junk cars, rusty bikes and garbage — and the cabin’s tattered innards — are anything but inviting.

First, a tangle of extension cords crisscrosses the lawn outside, powering a still-lit string of Christmas lights hanging off a stand-alone garage, and the grounds are dotted with great piles of firewood to feed the house’s old wood-burning stove.

Several half-empty milk gallons dating as far back as September fester in a nearby snowbank next to a scorched disposable baking tin.

Multiple empty containers of Cranberry Smirnoff Ice, Grape Henry’s Hard Soda and black cherry White Claw Hard Soda are heaped in the rubbish alongside an empty but new-looking package of 80 Member’s Mark brand female adult diapers.

Other garbage includes soft-drink cans including of A&W Root Beer and empty bags of junk food such as Cheetos.

Inside, the cabin looks as if it’s still being constructed, with ceiling insulation visible in a second-story den.

A book titled “U.S. Armed Forces Survival Guide” lies on a table, and an open Monopoly set is on the floor a few feet away.

Several mismatched rocking chairs fill the cluttered room, which is finished in half green shag carpet and half linoleum.

The fixture on a sink in an attached kitchenette appears to be made of PVC pipe, and dishes are piled in and around the sink.

Lights were on Sunday, but no one answered the door at the two-story home.

An aerial shot of the isolated but unassuming home shows it covered in snow and in a wooded area about 200 feet from the nearest road.

Patterson used to live at the cabin with his father and brother, but his dad transferred ownership to Superior Choice Credit Union on Oct. 23 — eight days after Patterson allegedly killed Jayme’s parents and snatched her from her home 80 miles away.

Authorities say Patterson acted alone.

Peter and Kristin Kasinskas, who helped rescue Jayme, told The Post on Sunday that the girl was “dirty,” “thin” and “really tired and run down” when they first saw her Thursday afternoon.

Her hair “was like a big dreadlock — like she’d been laying down,” Kristin said at her Wisconsin home.

Peter added, “She hadn’t taken a bath for weeks if at all.”

Neighbor Jeanne Nutter brought Jayme to the Kasinskases’ after she found the girl wandering in a daze Thursday.

Jayme was wearing a zip-up hoodie, leggings and ill-fitting men’s sneakers, the Kasinskases said.

“She was very calm,” Peter said. “She kept saying, ‘I’m Jayme, I’m Jayme.’ ”

The adults said they knew Jayme’s accused captor allegedly killed the girl’s parents — so they weren’t about to take any chances.

“Jeanne said, ‘If you have a gun, get it ready. We don’t know if he’s coming here,’ ” Peter said. “I got my firearm out and stood by the door until the police arrived.”

After officers arrived at the home and took Jayme to safety, they told Kristin and her kids to get away from any windows in case the abductor came to the home.

Jayme has been reunited with relatives, who shared pictures of the girl smiling with her aunt and dog.

“As a family we will get through all of the healing process Jayme has,” aunt Jennifer Smith wrote on Facebook. “It will be a long road but we are family strong and we love this little girl so much!!”

Additional reporting by Max Jaeger, Tamar Lapin and the Associated Press