Question: Plainfield High School is part of a school district headquartered where?

Context articles: North Plainfield High School
Plainfield East High School
Plainfield Central High School
United School District (Pennsylvania)
North Plainfield School District
Plainfield High School (New Jersey)
Plainfield South High School
Plainfield High School (Plainfield, Indiana)
Plainfield North High School
Plainfield Community School Corporation

North Plainfield High School is a four-year comprehensive public high school serving students in ninth through twelfth grade from North Plainfield, in Somerset County, New Jersey, United States, operating as part of the North Plainfield School District.
 The school is fully certified by the New Jersey Department of Education and accredited by the Middle States Association of Colleges and Schools Commission on Secondary School since 1929.
Plainfield East High School, or PEHS is a four-year public high school located in Plainfield, Illinois, a southwest suburb of Chicago, Illinois, in the United States.
 It is part of the Plainfield Community Consolidated School District 202, which also includes three other high schools: Plainfield Central High School, Plainfield South High School, and Plainfield North High School.
Plainfield High School - Central Campus, or PHS-CC, is a four-year public high school in Plainfield, Illinois, a southwest suburb of Chicago, Illinois, in the United States.
 It is part of Plainfield Community Consolidated School District 202, which also includes three other high schools: Plainfield South High School, Plainfield North High School and Plainfield East High School.
United School District is a small, rural public school district headquartered in East Wheatfield Township, Indiana County, Pennsylvania, United States.
 The United School District encompasses approximately 131 sqmi .
 The district serves the borough of Armagh and the townships of Brush Valley, Buffington, East Wheatfield, and West Wheatfield.
 According to 2000 federal census data, United School District served a resident population of 8,269.
 By 2010, the district's population declined to 7,988 people.
 The educational attainment levels for the School District population (25 years old and over) were 82.9% high school graduates and 10.9% college graduates.
 The district is one of the 500 public school districts of Pennsylvania.
The North Plainfield School District is a comprehensive community public school district that serves students in pre-kindergarten through twelfth grade from North Plainfield in Somerset County, New Jersey, United States.
 The district also houses a comprehensive Adult High School and an Adult Community School which offers educational programs for North Plainfield and neighboring community residents.
Plainfield High School is a comprehensive community four-year public high school that serves students in ninth through twelfth grades from Plainfield, in Union County, New Jersey, United States.
 The school is part of the Plainfield Public School District, one of New Jersey's 31 former Abbott districts. Plainfield High School was established in 1857, making it the second-oldest high school in New Jersey.
 The school has been accredited by the Middle States Association of Colleges and Schools Commission on Secondary Schools since 1928.
Plainfield South High School, or PSHS, is a four-year public high school located in Joliet, a southwest suburb of Chicago, Illinois, in the United States.
 It is part of the Plainfield Community Consolidated School District 202, which also includes three other high schools: Plainfield Central High School, Plainfield North High School and Plainfield East High School.
Plainfield High School (abbreviated PHS) in Plainfield, Indiana.
 It is a public high school located within the Plainfield Community School Corporation.
Plainfield North High School, or PNHS, is a four-year public high school located in Plainfield, Illinois, a southwest suburb of Chicago, Illinois, in the United States.
 Founded in August 2005, it is located on 12005 S. 248th Ave and is part of Plainfield Community Consolidated School District 202.
 It currently serves students who live in northern Plainfield and parts of Romeoville and Naperville.
Plainfield Community School Corporation (PCSC) is a school district headquartered in Plainfield, Indiana.