Nora Clavicle and the Ladies' Crime Club - S3-E19
Visible crew/equipment: When Batman and Robin are seated in the Batmobile with Batgirl standing alongside, while they listen to the ridiculous police dispatcher, the reflection of the moving boom mic is visible on the front windshield's chrome trim. (00:10:00)
Visible crew/equipment: At the Gotham City Opera House, after the Terrific Trio have taken care of Shame and his men, Calamity Jan and Frontier Fanny show up and spray the heroes with fear gas. When Shame and his gang walk over to Batman, Robin, and Batgirl, a few chalk T-marks are visible on the floor where they will stand. (00:17:45)
The Great Train Robbery (2) - S3-E22
Visible crew/equipment: When Shame has finished reading Batman's skywriting message, as he says, "Darned if I won't be there," the shadow of the boom mic dips into view at the top of the green door, at the right side of the screen. (00:17:20)
I'll Be a Mummy's Uncle - S3-E23
Visible crew/equipment: When King Tut runs back up the shaft and encounters Batgirl, Commissioner Gordon, and Chief O'Hara, he is reveling giddily in the truth he has discovered. Then, when Batman and Robin show up, their chalk T-marks are visible on the ground. (00:21:10)
The Entrancing Dr. Cassandra - S3-E25
Visible crew/equipment: While Batman and Robin are at GCPD, Batman decides to use the library to research occult sciences, and when it cuts to Cassandra and Cabala returning to their hideout they walk over to the table, and behind them we can see the chalk marks on the floor by the door, where they previously stood. (00:05:15)
The Entrancing Dr. Cassandra - S3-E25
Visible crew/equipment: After Batman discovers Cassandra's true identity in the alchemy book, he takes a call from Commissioner Gordon on his cute portable Batphone, then he and Robin head to Spiffany's. When it cuts to Spiffany's, just as narrator William Dozier says, "Gotham City's fashionable 15th Ave," the actor's white marks are visible on the floor under the table. Then we see Cassandra's and Cabala's white T-marks when they walk in. Next, upon the Terrific Trio's entrances, we see their T-marks as well. (00:08:25)
The Entrancing Dr. Cassandra - S3-E25
Visible crew/equipment: After Alfred has placed the two-dimensional Terrific Trio into the Three-Dimensional Bat-Restorer, when they all walk out of the chamber, two chalk T-marks are visible on the floor. First we see Batgirl's T-mark and then Robin's. (00:16:50)
Minerva, Mayhem and Millionaires - S3-E26
Visible crew/equipment: At the start, in the two consecutive scenes with millionaires William Dozier and then Howie Horwitz, while they're being treated to Minerva's renowned scalp massage, the chalk T-mark is visible on the floor at the lower left side of the screen, and in the Horwitz scene Minerva's small mark is also visible on the floor behind the spa chair. (00:00:45)
Minerva, Mayhem and Millionaires - S3-E26
Visible crew/equipment: Minerva tells Freddie that if she'll get the diamonds from the Wayne Foundation vault, he can fence them. When it cuts to Commissioner Gordon, Batgirl, and Chief O'Hara pacing the floor, three small white tape marks are visible on the rug in front of the coffee table, where each of them stop and turn on their marks. (00:05:35)
Answer: There wasn't one singular city used. It was shot in and around various locations in California, plus on a lot of sets and backlots. Ex. Some scenes were shot in LA, some in Pasadena, some in Santa Barbara, etc.
TedStixon