Are the SAT test dates posted by the College Board the same for all high schools in the United States? Or are there tests given at different times in different parts of the country?
No. Not every high school is a College Board SAT Testing Center, and not every testing center offers the SAT on every test date. To check if a certain testing date is offered at your high school, you'll need to go to the College Board website and select the date, your country, and your state. You can narrow it down to the city as well, but I've found that sometimes the College Board thinks your high school is located in a neighboring town, so it's easier to just get a list for all of the schools in the state and then search your high school's name.
This is just as true when it comes to taking SAT Subject tests, since many of the subject tests are only offered a few times a year nationally (let alone at any particular testing center).
For more information on SAT test centers, read our articles on where you should take the SAT and how to choose a good SAT testing location. And if you think you might need to request "testing closer to home," be sure to read our guide on how to request it.