Primary education in the United States  Primary education in the United States (also called elementary education) refers to the first seven to nine years of formal education in most jurisdictions, often in elementary schools, including middle schools. Preschool programs, which are less formal and usually not mandated by law, are generally not considered part of primary education. The first year of primary education is commonly referred to as "kindergarten" and begins at or around age 5 or 6. Subsequent years are usually numbered being referred to as "first grade", "second grade", and so forth. Elementary schools normally continue through sixth grade, which the students normally complete when they are age 11 or 12. Some elementary schools graduate after the 4th or 5th grade and transition students into a middle school. In 2016, there were 88,665 elementary schools (66,758 public and 21,907 private) in the United States. Some private schools, and some public schools, are offering pre-kindergarten (also known as pre-K) as part of elementary school. The first three to five years of an individual’s life can be the most critical period of their education (nursery school). During this time period young minds work on several physical, intellectual, and emotional developments, including curiosity, formation of character, personality, cognition, language skills, and social skills. Since 1965, the federal government has promoted the growth of state-funded programs such as Head Start, a program under the United States Department of Health and Human Services. In 2007, it served over 22 million preschool-aged children and their families. Head Start works to educate the whole child in addition to providing health and nutrition services to low-income families. Students may attend either a 5-year, 6-year or 7-year public or private elementary school. Elementary school usually runs from kindergarten or 1st grade through either 5th or 6th, depending on the region. Upon successful completion of their elementary education students then proceed to middle school, (High School in the UK) also known as junior high school. Depending on the school district, some students attend separate middle schools, beginning at 6th grade and then completing at 8th grade before they transition to high school. Additionally, students may have the option of attending elementary schools that include all eight primary grades. In this case, the student will directly proceed to High School. In most U.S. elementary schools, students have all their core classes from one or two homeroom teachers (as opposed to middle and high schools that typically have students rotate from one specialized teacher to the next throughout the day).