What to do about continuous barking by neighbor's dog, even through the night? What are regulations, and how to file a complaint? The dog is in stress too.

Call the police you shouldn't have to put up with that

I agree with Karen, you should try to talk to them first. If that doesn't work or maybe you already have a poor relationship with your neighbor you can call the police after 10pm.

Have you spoken to the neighbors? Calmly & courteously, of course. If that is not possible or has not worked you can file a complaint with county animal control.

Jamie is right, talk first and take action after 10pm.