According to this, they should all be in the basement of Mortar and Pestle Building on Abracadabra Alley.
8 seconds sound clip from Batman (1966) - The Entrancing Dr. Cassandra (S3E25) TV Series.
You can hear this line at 00:18:01 in the Blu-ray version of the movie.
Quote context
[...]
- Dr. Cassandra has engineered an incredible mass escape of all of Gotham City's arch-criminals.
- Which calls for the Special Escaped Archcriminal Bat-locator in the Batcomputer.
- That must come in quite handy.
- Quite. Every crime fighter should have one.
- But how can we get there? Isn't the Batmobile still parked in front of Spiffany's Jewelry?
- Now, how in the world did you manage that?
- There's no time for that now, Batgirl. To the alley.
- I'm afraid I'll have to put you to sleep until we reach the city, Batgirl.
- So you won't learn the location of the Batcave.
[...]