So from my understanding, school districts are only comprised of public schools (including charter schools) and can either be independent or dependent. If they're independent, they rely on themselves for funding and tax money, but if they're dependent, they rely on either the local or state government for funding and regulation. And when they're independent, they can make their own rules as long as they don't contradict those made by the state or county, kind of like a state's relationship to the country. But my question is, since school districts can cross over to more than one county or more than one state, how do they know who's regulations to follow if they're independent, or who they're getting taxes/funding from if they're dependent?

Is this homework? It's a simple answer. In the U.S. you can view school districts' policies and procedures, including funding online.

Each school district is just that, able to set their own rules for their districts. Seldom is there really any independent schools, if they report to the district, since as such, they are under the districts rules and regs.

Never saw a school district extend outside a county and particularly a state boundary. Where did you get your information to make such a statement?

School districts are government entities on the county or city level. Never seen it any other way. A public school is run under the local district. A private school is not. I've never heard of the designation dependent or independent.

Never saw a school district extend outside a county and particularly a state boundary. Where did you get your information to make such a statement?

It's not uncommon. There are towns that span across county lines, and it wouldn't be unusual for the school district serving that town to also span county lines. For example Naperville IL is served by two school districts, both of which sit in parts of two different counties. And there are cities that encompass multiple counties - NYC comes to mind; it contains five counties, run by one school administration. As for districts that cross state lines, I am aware of two: the Rivendell School District covers three VT towns (Fairlee, West Fairless, and Vershire) as well as Bradford NH (fans of "The Lord of the Rings" will recognize the "Rivendell" name), and just a little further south the schools of Hanover, NH and Norwich VT are also incorporated into a single district. There may be others, but they are certainly unusual. The establishment of these cross-state districts required agreements between both states' boards of education. Do a search on Rivendell School District and you'll find links to the documents that authorized creation of the district.

To the OP: as for terms "dependent and "independent" - the term "Independent School" is sometimes used as a synonym for "private school." For example the National Association of Independent Schools is a consortium of private schools. But it seems you are using these terms for public schools, which I've not heard before.