County boundaries at sea

[yogasun]

No idea what category to put this in!
Where do county boundaries end at the seashore? Am asking for my son who is a bird recorder. Do they extend out so sea for any distance?
Any help appreciated. Off to work soon. Thanks.

[heathfield]

You could plough through this - it might give what you're looking for...

http://jncc.defra.gov...ldesley_reportall.pdf

[yogasun]

Thanks heathfield

Will do.