Past question papers for statewide or national exams are often located on the website of the examining board. In addition, testing companies may sell books containing past exams. Past exams administered by individual schools are not usually available online, but can be acquired from school administrators or teachers.
Past papers for state-administered exams are often available on the website of the state education board. For example, the New York State Education Department posts past question papers from the high school Regents Examinations online. The Massachusetts Department of Education also posts past examinations from state tests and also provides sample answers and scoring guides.
A small number of papers from exams run by the College Board, such as the SAT and Advanced Placement tests, are available online. The College Board only posts one full-length SAT test at a time, but changes the posted test each year. However, the College Board also sells a book called "The Official SAT Study Guide" which contains previous SAT tests. The College Board website also includes a small number of past papers for Advanced Placement exams, each of which is posted on the webpage for the individual subject.