The chief town of the Shire in the White Downs, that lay in the Westfarthing of the Shire. Its name means simply 'large excavation'.
Notes
1
We have no date for the foundation of Michel Delving, but its size and its status as chief township both point to a foundation early in the Shire's history.
2
'Michel' comes from Old English Micel. In Old English, the letter 'c' (in these circumstances, at least) would normally be pronounced as modern 'ch'. So, in rendering the name 'Michel', Tolkien simply seems to be adjusting the spelling to make it simpler for a modern audience to read and pronounce.
3
Micel is Old English for 'big', 'great': it version of it also occurs in Mickleburg, a Mannish name for the Dwarf-city of Belegost. It serves to distinguish this larger township from Little Delving that stood to the north.