Public education is universally available. School curricula, funding, teaching, employment, and other policies are set through locally elected school boards with jurisdiction over school districts with many directives from state legislatures. School districts are usually separate from other local jurisdictions, with independent officials and budgets. Educational standards and standardized testing decisions are usually made by state governments.

The ages for compulsory education vary by state. It begins from ages five to eight and ends from ages fourteen to eighteen.[4] Compulsory education requirements can generally be satisfied by educating children in public schools, state-certified private schools, or an approved home school program. In most public and private schools, education is divided into three levels: elementary school, middle school (sometimes called junior high school), and high school (sometimes referred to as secondary education).

In almost all schools at these levels, children are divided by age groups into grades, ranging from kindergarten (followed by first grade) for the youngest children in elementary school, up to twelfth grade, the final year of high school. The exact age range of students in these grade levels varies slightly from area to area.
Post-secondary education, better known as "college" in the United States, is generally governed separately from the elementary and high school system, and is described in a separate section below.

Source: http://en.wikipedia.org/wiki/Education_in_the_United_States