Spencer, Aria, Emily, and Hanna went searching in several places to follow mysteries and narrow down who could be A. Their searches took them all over Rosewood and outside as they occasionally traveled to New York.
While some places turned out to be nothing more than dead ends, others were essential to answer questions or leave impacts on the girls. Nowhere was too far to go to get answers even if it meant going into uncertain territory. Also, when some places did not have what they were looking for, others did a remarkable job of continually being relevant throughout the seven seasons.
Ravenswood
When Alison knew she was being watched, she went to Carla Grunwald for help. Alison's trek leads her to Ravenswood. In season four, her friends end up in Ravenswood, believing they are closer to solving the ever-growing mystery of Alison and A. The Liars find what appears to be an A Lair in Ravenswood with logs of payroll and cameras showing they were being watched. Later, Ezra shows up in the room, angry, revealing that the place and research were all his. Ezra later confirms it by telling Aria about his desire to write a true-crime book about Alison. Ravenswood was also the primary setting of the short-lived Pretty Little Liars spin-off, Ravenswood.
Alison's House
Alison's house was a central location regarding the truth about what happened to Alison, leading up to her disappearance. Several ing characters had been involved in an activity at or around Alison's house the night of her disappearance. Alison's lawn was where she was buried alive, unknowingly at the time.
However, when Alison's body is found at the house, where Maya had been living at the time, it is another few seasons before discovering that the girl wasn't Alison at all, but Bethany, another girl with blonde hair wearing the same yellow shirt. In season six, the moms end up stuck in the basement of the house.
Spencer's Barn
Spencer's Barn was where the girls were when Alison disappeared and also counted as a place of residence throughout the series. Melissa and Wren both live in the Barn in the early episodes, and after the time jump, Spencer lives there, and it is the central location where they play A.D's board game. They also hold their makeshift prom in the Barn after the school prevents the girls from attending the dance after escaping the Dollhouse. After the time jump, Spencer finally gets to live in the Barn like she had hoped to do while she was still in high school.
Rosewood Police Station
The Rosewood Police may not have been the most useful, but the girls spent plenty of time at the station. It also helped that Toby started working there. The girls knew about the goings-on at the station and what the police knew. All of the girls have been arrested at different points. It also showcased the girls' troubles with the police and how far Ashley Marin was willing to go to protect Hanna after Hanna was caught shoplifting. Ashley made a deal with Officer Wilden, something that kept the curious police officer in Hanna's house far more often than she'd like.
Lost Woods Resort
The Lost Woods Resort was the first known A Lair in the series. Already holding an eery vibe about it, A's lair is even more disturbing than the rest of the motel. There are pictures on the walls of Aria, Alison, Spencer, Emily, and Hanna, almost as if it was a shrine. Mary Drake eventually owned the Lost Woods Resort.
Later, she ed the deed on to Spencer and Alison, making them co-owners. The Lost Woods Resort occasionally appears throughout the series through flashbacks showing Alison and Mona's last moments together just before Alison was declared missing.
London
When A.D. is finally revealed to be Alex Drake, Spencer's twin sister, it comes with flashbacks to explain the backstory of Alex and her relationships with Charlotte, Wren, and Archer Dunhill (also known as Dr. Elliot Rollins). Explaining how Alex knew about the Liars in the first place, Alex told Spencer that Alex had met Wren at a bar, and he had mistaken her for Spencer. Later on, Wren had connected with Alex and Charlotte to reunite the relatives. London was essential to connect the four villains and how they each connect back to everyone in Rosewood.
Dollhouse
From bedrooms that were exact replicas to the real thing to the alarms and tortures, the Dollhouse left one of the most massive impacts on Pretty Little Liars. The Dollhouse only counts as a central setting for two episodes, but it does recur in flashbacks and leaves emotional, mental, and physical scars and changes on the girls. Even after they escape, it stays with them, from images appearing at Aria's art show to discovering that A had chipped them when they were unconscious. The Dollhouse is also the first place the girls learn about Charles and that A does have a soul.
Radley Sanitarium
Everything leads back to Radley. Radley Sanitarium became a significant location when Mona was a patient and remained a suitable place after she left. Even if Radley didn't appear for several episodes, the reveal about Cece Drake, being Charles, being Charlotte, all lead back to Radley and intertwined with the truth about Toby's mother. Plenty of loose ends made their way back to Radley Sanitarium, and the girls continually found themselves going back for information.
After the time jump, Radley Sanitarium was transformed into an upscale hotel. Even after its transformation, parts of the original Radley still found ways to seep in, and the Liars found themselves laughing at Radley's change from Sanitarium to the hotel.
Rosewood High School
To keep the central characters together, their last two years of high school lasted six seasons. Mona used her connections, classmates, and other ways to gain information about Aria, Spencer, Hanna, and Emily. The girls would receive messages from A many times during school throughout their junior and senior years. Even after they graduated, Alison's job as a teacher kept Rosewood High School as a suitable location. Rosewood High School was at the center of many of A's schemes, no matter if it was to throw them off the scent or to cause a scene.
Rosewood (The Town)
Although places within the town are already listed, the town itself was the most central location of all. Nearly everything massive happened in Rosewood, and if it did not occur there, it was definitely to the residents of the town. Rosewood could be a playground for A, watching as the Liars tried to weed out different possibilities and theories to discover who was behind the messages. To get the Liars to do what she wants, A.D. created a game board designed to look like the town of Rosewood. They do not all remain in Rosewood at the end of the series. However, the finale does hint that the town still holds mysteries to be unraveled.