I wondered to myself if there was a specific point within the 12 mile US territorial sea where individual U.S. state law ends and only federal law applies. For example, could an individual/business create an offshore site that is just outside of the local state's legal reach but still under federal law? To my surprise I could not find anything general like: "State law ends 3 miles from shore" or "State law ends 1 mile from shore". Apparently there's ambiguity.
Found a summary here:
There has been tension for decades between the federal government and the states over who has control of the waters out to the three-mile — and more recently 12-mile — limit. The tension has been largely over control of mineral rights rather than how other laws are applied. Offshore wind and state laws
Is there a line at all?
I'm confused... if it's unclear where state laws end and federal law begins how do local authorities even know when to call the feds when they find something suspicious/"criminal" offshore?
How do individuals even know which, if any, state laws apply when they are offshore? But remember that my question is about the border line(s) so saying simply that there's a list of water patrol laws for a particular jurisdiction would not (in my view) answer the question.
I found an example of a kind of border in "The Marine Unit members are also cross-certified Immigration and Customs Enforcement Officers, and are empowered to enforce federal regulations far beyond the limits of State of Florida jurisdiction." Marine Unit, manateesheriff.com. But it doesn't really answer the question.