The wood has been consistently named as "Molly Carr Wood" on Ordnance Survey maps since the 1850s ("carr" meaning wood), although there is little evidence that this is the correct or preferred spelling. "Mollicar" is the only spelling which appears in the Huddersfield Chronicle archives (1850-1900) and is the preferred spelling in local naturalist publications.
It is sometimes apocryphally claimed that Molly Carr was a local woman, although the surname is rare in the area and the only baptism for that name found during research was for the daughter of James Carr of Heckmondwike who was baptised on 12 August 1792 at Huddersfield Parish Church. However, as this Molly Carr seemingly doesn't appear in the 1841 Census, she had presumably either died by then or had married and taken a different surname.
Whilst the suffix "Carr" normally refers to a wooded marshy area — from the Old Norse kjarr, meaning a swamp — it has been suggested that "Molli" may refer to birds of prey such as kestrel or kites.
The annual Whit Sunday Sing was begun by choirmaster Arthur Swift of the Zion Wesleyan Reform Chapel in Almondbury in either 1906 or 1907. According to some sources, Swift had suggested the choir might prefer to practise Whitsuntide hymns outdoors early one morning. However, the choice of location and time may be linked to the fact that nightingales were known to have sung in the wood at dawn and dusk during May.
By the 1930s, the early morning Whit Sunday Sing was attracting upwards of 8,000 people. After the 1930 sing, the choir members spent time repairing the dry stone walls which had been damaged by the crowds.