Althorp ( or ) is a Grade I listed stately home, estate and small civil parish in Daventry District, Northamptonshire, England of about . By road it is about northwest of the county town of Northampton and about northwest of central London. It has been held by the prominent aristocratic Spencer family for more than 500 years, and has been owned by Charles Spencer, 9th Earl Spencer since 1992. It was also the home of his sister, Lady Diana Spencer later Princess of Wales, before her marriage to Charles, Prince of Wales.