Chappaqua is a hamlet in northern Westchester County. As of the 2010 census, following a major revision to the boundaries by the Census Bureau, the population was 1,436. (At the 2000 census, with very different boundaries, Chappaqua had a population of 9,468) Chappaqua is located in the town of New Castle.

Chappaqua Central School District - Today, the schools in Chappaqua are reputed to be among the best in the country, but this was not always so. Small one-room schoolhouses devoid of windows were prevalent in the 1800s.

Parent expectations in the school district are high, and the educational environment has been described as highly competitive and somewhat stressful.

The district's modern commitment to education was exemplified in the 1950s when Horace Greeley High School principal, Donald Miles, began hiring teachers based primarily on their subject knowledge, eschewing the "professional teacher". One of the most notable hires was Edwin Barlow, a math teacher whose controversial classroom methods and enigmatic life are chronicled in the 2009 memoir, Teacher of the Year: The Mystery and Legacy of Edwin Barlow. One of the current (2011) Chemistry and AP Chemistry teachers, Richard Goodman, won the "Chemistry Teacher of the Year" award in 2009.

Horace Greeley High School is home to the Chappaqua Summer Scholarship Program, which brings motivated and aspiring students to Chappaqua for four weeks over three summers to take classes while living with host families in Chappaqua.

Parts of the Chappaqua ZIP code area are located in the towns of Mount Kisco, New Castle, Mount Pleasant, Yorktown, and Bedford, as well as the hamlet of Millwood. Parts of the Chappaqua Central School District include homes in other zip codes, such as 10570, the Pleasantville zip code.