Mecklenburgh Square is a Grade II listed square located in the King's Cross area of central London. The Square and its garden were part of the Foundling Estate, a residential development of 1792 — 1825 on ﬁelds surrounding and owned by the Foundling Hospital. The Square was named in honour of King George III’s Queen, Charlotte of Mecklenburg-Strelitz. It was begun in 1804, but for various reasons was not completed until 1825.
It is notable for the number of historic terraced houses that face directly onto the square and the Mecklenburgh Square Garden. Access to the garden is only permitted to resident keyholders, except on two days a year when it’s open to all visitors for Open Garden Squares Weekend.
The garden was laid out and planted between 1809 and 1810 as the centrepiece of the newly developed Mecklenburgh Square. The 2 acres (8,100 m2) garden is made up of formal lawns, gravel paths, mature plane trees and other ornamental trees. It contains a children's playground,and a tennis court. The east side of the garden is planted with plants native to New Zealand.
To the west is Coram's Fields, a playground for children, and to the east is Gray's Inn Road, a major thoroughfare for the area. Goodenough College is a postgraduate residence and educational trust on the north and south sides of the square, and operates an academic-oriented hotel on the east side.
- Karl Pearson lived at no. 40 as a child from 1866-1875.
- At number 21 there is a blue plaque for R. H. Tawney (1880 - 1962), historian. In the same doorway is a blue plaque for Sir Syed Ahmed Khan (1817-1898).
- At no. 44 there is a plaque (though not an English Heritage one) for H.D. (Hilda Doolittle 1886 - 1961), the American poet.