Another possibility is to look at the list of members of the Jewish Cemetery Association of North America:
https://www.jcana.org/members/all-members
Some of the members are cemeteries, and some are regional associations, such as the Jewish Cemetery Association of Massachusetts, which has address information on over 200 Jewish cemeteries in the state, even if they are not members of the association:
https://www.jcam.org/Pages/Cemeteries/Cemetery_Pages/Alpha_by_Name.htm
Note in this case they list 222 cemeteries, while JOWBR lists 158 cemeteries, and the IAJGS site lists 62 burial locations for the state. Some of the discrepancy may have to do with how cemeteries are defined, and if a cemetery with 10 sections owned by different organizations is considered one cemetery or 10, but either way this kind of checking should provide more information.