Founded in 1875, the school moved in 1974 to the Aldenham estate in Elstree. It is on a single, semi-rural site comprising 43 acres of fine park and woodland, adjoining the boys' school. It has first-rate modern facilities, most recently a new junior school. Academic standards are very high and examination results are consistently excellent; very many sixth formers annually go on to Oxbridge. Immensely strong in music with a variety of musical groups. Drama and art are also strong. It has a very good range of games and sports in which high standards are achieved (several representatives at county and national level). A wide variety of activities is available, some organised jointly with the boys' school It has an outstanding record in the Duke of Edinburgh's Award Scheme.

Pupils: Total age range 4-18; 1110 day girls. Senior department 11-18, 815 girls. Entrance: Main entry ages 4, 5, 11 and 16. Own entrance exam used; for sixth-form entry, 5 GCSEs at least grade C, including maths, English and a language (grade A in sixth-form subjects). All special skills welcomed. State school entry 45% main senior intake, plus 50% to sixth form.

Some scholarships at 11, value 500-2000 pa, including music scholarships and awards. Some governors' bursaries up to full fees. Parents not expected to buy textbooks; maximum extras, 100 per term.

Head Mistress: Mrs Elizabeh Radice, in post from 2005. Educated at Wycombe Abbey and Oxford University (English). Previously Headmistress at Channing School, Head of English at St Helen and St Katharine and Director of Studies at Royal Grammar, Newcastle. Teaching staff: 86 full time, 24 part time. Annual turnover 10%. Average age 37.

GCSE: 111 pupils in upper fifth, all gained at least grade C in 8+ subjects. Average GCSE score 75 (72 over 5 years). A-levels: 137 in upper sixth. 20% passed in 4+ subjects, 78% in 3 subjects. Average final point score achieved by upper sixth formers 360.

98% of sixth-form leavers go on to a degree course (some 20% after a gap year), 30% to Oxbridge. 20% take courses in medicine, dentistry and veterinary science, 10% in science and engineering, 65% in humanities and social sciences, 5% in other vocational subjects eg education, pharmacy.

GCSE, AS and A-levels. 21 examination subjects. Sixth form: Most sixth formers take 4-5 subjects at AS-level (often including contrasting subject), 3 at A-level; general studies taught but not examined. 25% take science AS and A-levels; 35% arts/humanities; 30% both. Vocational: Work experience available in UK and Europe. Languages: French, German and Spanish offered at GCSE, AS and A-level; also AS-level Italian (in sixth form), Japanese (usually non-examined, from age 5). All girls study French from Year 6, Latin from Year 7, German or Spanish from Year 8. Regular exchanges (France, Germany and Spain). Links with 5 schools in France, others in Germany and Spain. Most classes are paired with classes in France, Germany or Spain and correspond (by email in Years 10 and 11); EYP and Euroscola in sixth form. ICT: Taught both as a discrete subject, in sixth-form general studies and across the curriculum. Over 200 computers for pupil use (8 hours a day), all networked and with Email and internet access. Intranet for each department, video screening facility.

Music: 75+% of pupils learn a musical instrument; instrumental exams taken by many. Some 20 musical groups including 4 orchestras, 2 wind bands, 9 choirs, choral society, jazz/big band. Carol Service at St Martin in the Fields; over 15 concerts a year (eg Mozart's Requiem). Drama and dance: Both offered; drama/theatre studies to GCSE and A-level. Many pupils are involved in inter-form performances, main school productions or in the boys' school plays. Recent productions include The Caucasian Chalk Circle, Canterbury Tales (2004), The Roses of Eyam (2003), Bus (joint with the boys' school. Art and design: GCSE, AS and A-level taken. Design, pottery, photography, screen printing, sculpture as part of course. Successful DT applications for national awards eg Arkwright Scholarships.

Sport: Lacrosse, netball, dance, gymnastics, swimming, tennis, athletics compulsory. Optional sports: badminton, fencing, trampolining, volleyball, riding, football, water polo. Sixth form only: squash. RLSS and sports leadership scheme exams may be taken. National lacrosse, swimming, badminton, fencing representatives; regional, district and county lacrosse, swimming, netball, athletics representatives; lacrosse, netball, gymnastics and trampolining teams successful in national and regional competitions. Activities: Pupils take bronze, silver and gold Duke of Edinburgh's Award. Community service optional and heavily subscribed. Weekly visits to local residential homes and riding for disabled, Christmas party for local elderly, Mencap Day, Up to 80 clubs, eg chess, debating, maths, science, Christian Union, Jsoc, poetry, computer, drama, gym, dance, Indian cultural.

Uniform: School uniform worn except in the sixth form. Houses and prefects: Prefects and head girl elected by school. School council. Religion: Christian. Compulsory assembly. Separate Jewish, Hindu, Jain assemblies weekly, Muslim assembly twice a term, Mass and Holy Communion. Social: Debates, quizzes and many extra-curricular activities with Haberdashers' Aske's Boys. Organised trips abroad. Meals self-service. No tobacco or alcohol allowed.

Pupils failing to produce homework might expect a reprimand; a girl smoking cannabis on the premises would expect to be expelled.