what grade is senior high

In the United States, high school typically includes grades 9 through 12. The last year of high school is referred to as senior year or 12th grade. Students in their fourth year of high school are considered seniors. The terms "freshman," "sophomore," "junior," and "senior" are used to describe what year of school someone is in. Freshman year is 9th grade, sophomore year is 10th grade, junior year is 11th grade, and senior year is 12th grade. Therefore, senior high refers to the last year of high school, which is 12th grade.