Lawrence School was started in tented accommodation, with a group of 14 boys and girls on the 15th April 1847. By 1853, the students numbered 195 and the school was presented the King's Colour, thus, making a member of the 6 elite institution, to be honoured by the British Empire, the others being Eton, Shrewsbury, Cheltenham, the Duke of York's Royal Military School and the Royal Military College, Sandhurst. Till 1857, Sir Henry, bore the financial expenses of the school, after his death, the British government to the responsibility.

The control of the school then passed to the crown, which was very unusual and never repeated for any British public school. Today, The Lawrence School, Sanawar, is a co-educational boarding school with students from different backgrounds. Red roof, paved paths, trees, flowers, exotic birds, view of snow clad peaks, rolling hills, valley view are the main characters of the school's surrounding. The buildings are naturally colonial and mostly century old.

The School Chapel is 149 years old and is the oldest among all the buildings. This Chapel has very exquisite stained glass windows.
Though the school does not have any specific religious affiliation, the Chapel is the spiritual centre of the community, regular assemblies are held, where all students and staff take part. A silent march past the War Memorials besides the Chapel is a daily routine.

This connects the pupils of today with those of the past who played a vital part when the nation needed. Central Dining Hall offering 3000 meals a day, indoor sports complex which has solar heated swimming pool and squash courts. A Library, Learning Resource Centre, Computer & Internet facility are all part of the Parker Hall (in the name of the first principal of the school, Rev. W.J. Parker, 1848-1863). This hall also has the privilege of getting the first ISDN line of Himachal Pradesh. The Birdwood, is the main teaching block and also contains the Barne Hall (in the name of the fourth principal, Rev. G.D. Barne, 1912-1932) , where plays, shows, films and lectures are regularly held. There are various playing fields, old cricket and football ground - Barne Field. Newly constructed Basketball court is one of the latest additions.

The Lawrence School - Sanawar is a self-sufficient institution with its own hospital, press, kitchens, laundry & shops. All daily requirements are supplied from Chandigarh, which is just an hour & a half drive from Kasauli. Chandigarh is also the nearest hub for other entertainment & educational activities. Sanawarians - as the school students call themselves for ages, enjoy the magical quiet spaces, where they sit and think. Sanawar has had a strong tradition for a very high standard military training and many contingents of boys were enlisted from the school straight on to the battlefields of the Great War. Thus, the school was redesignated in 1920 as the "Lawrence Royal Military School" and in 1922, the Prince of Wales personally presented the School with new colours. This Colour is still paraded every year at the Founders Celebration in early October.

Sanawarians still continue making a major contribution to the Indian Defence Forces by joining in good numbers. Sanawar's Centenary year (1947) was crucial to the development of the School. With Independence, the bulk of the staff and children at Sanawar returned to the UK. However, the then Governor General, Lord Louis Mountbatten, presided at the School's Centenary celebrations and read out a special message from George VI. Thereafter, control of the School passed from the Crown to the Government of India, Ministry of Defence. A further transfer in 1949 brought the School under the control of the Ministry of Education and subsequently, in 1953, to the autonomous Lawrence School (Sanawar) Society. However, Sanawar retains strong links with its past. The Chairman of the Society is the Secretary for Education, Government of India and, at the recent sesquicentenary celebrations in 1997, a message of congratulation was received from the current Prince of Wales, Prince Charles.

Principals as per the dates were: Rev. W.J. Parker (1848-1863), Rev. J. Cole (1864-1886), Rev A. Hilldersley (1886-1912), Rev. G.D. Barne (1912-1932), Mr. E. G. Carter (till 1956), Maj. R. Som Dutt (1956-1970), Mr. S. R. Das (1974-1988).