A village in the Westfarthing of the Shire lying on the Great East Road 'a mile or more' to the East of Hobbiton and forming a single community with it. The most prominent feature was the Pool of Bywater and it's premier hostelry was the Green Dragon.

It was to Bywater that Bilbo Baggins ran from Bag End without hat or handkerchief to meet Thorin and Company at the start of the Quest of Erebor. Tolkien's map suggests that it is four miles from Hobbiton, but since Bilbo ran it in 10 minutes, we can suppose a distance of 'a mile or more' as stated in The Hobbit.

NOTE: Additional information from Cirdaneth.
Encyclopedia entry originally written by tsproffitt