Only 12 states:
* California
* Connecticut
* Florida
* Hawaii (in general a one-party state, but requires two-party consent if the recording device is installed in a private place)
* Illinois (debated, see next section)
* Maryland
* Massachusetts
* Montana (requires notification only)
* Nevada
* New Hampshire
* Pennsylvania
* Washington
https://en.wikipedia.org/wiki/Telephone_recording_laws#Unite...
But ironically you can go to prison in many states in the USA if you record calls without the other party agreeing.