Short answers, pulled from the story.
Bag End sits at the top of The Hill on the north side of Hobbiton in the Shire's Westfarthing. This location represents a luxurious smial or Hobbit-burrow dug into The Hill where Bilbo and Frodo Baggins lived.
The real name of the Tudor home dated to 1413 of Tolkien's aunt Jane Neave in Dormston Worcestershire was Bag End. Andrew Morton wrote an account of his findings regarding this connection for the Tolkien Library.
Peter Jackson built an elaborate Hobbiton film set on the Alexander sheep farm at Matamata in New Zealand that included Bag End in a small hill with garden. The set featured a water-mill, the Green Dragon Inn, and several Hobbit-holes alongside the circular green door of Bag End.
Johanna Brooke suggests that Bag End is an Arts and Crafts building fitting into ideas of designer William Morris between 1880 and 1920. Features such as panelled walls, tiles, and carpet could have been manufactured by Morris & Co to reflect middle-class prosperity.
Tom Shippey writes that the name Bag End is a direct translation of the French cul-de-sac meaning bottom of a bag or a dead end road with only one outlet. This interpretation aligns with the fact that both hobbits start and end their adventures in Bag End while returning there for a while after dangerous places.