Muggles' Guide to Harry Potter/Places/Shell Cottage

General Overview
Shell Cottage is the cottage on the oceanside where Bill and Fleur reside after their marriage.

Extended Description
Ron stays at Shell Cottage over Christmas of Harry's seventh year, when he apparates away from Harry and Hermione after their fight. This is also where Harry, Ron, Hermione, Luna, Dean, Mr. Olivander and Griphook take shelter after the fight at Malfoy Manor, and is the place where Dobby is laid to rest. With all of these people, the cottage is quite crowded, particularly as Griphook requires a room of his own, and Harry will, at least initially, not let Bill send Griphook or Mr. Ollivander to a different safe-house. We hear at one point that Harry, Ron, and Dean are sleeping in the living room. Lupin visits while Harry is there, to announce the birth of his son Teddy. And Ron, Harry, Hermione, and Griphook depart from there on their mission to enter Bellatrix Lestrange's vault at Gringotts.

The location of the cottage is protected by the Fidelius charm; the secret-keeper is Bill Weasley.

In post-publication interviews, the author has suggested that Shell Cottage is located on the outskirts of Tinworth, in Cornwall.

Analysis
We know very little about Shell Cottage; its appearance in the series is fleeting, and all we ever learn about it is that it is a safe house, inaccessible to those who have not had the secret of its location revealed to them by the secret-keeper, Bill Weasley. This actually leads us to one unresolved issue: how is Harry able to find it? It is possible, given that House-elf magic is distinct from Human magic, that Dobby may be able to find Shell Cottage despite the workings of the Fidelius charm, and Ron has stayed there for a while and so knows about it, but Mr. Ollivander, Dean, Hermione, and Harry, according to our understanding of the charm, should not even be able to see Shell Cottage until Bill tells them where it is. (Griphook may suffer the same effect, but as Goblins likely use a non-Human mode of magic, we cannot be sure.) It may be enough for Bill to greet them, saying something as mundane as "Welcome to Shell Cottage," but as far as we can tell, that does not happen; Harry arrives with the dying Dobby, and is able to see Shell Cottage immediately when he lands. No explanation for this is ever offered.

It is not immediately obvious why Harry does not want Griphook or Mr. Ollivander moved, despite the crowding in the cottage. Of course, immediately after their arrival, Harry does need to talk to Ollivander about wandlore, specifically to determine how much of a threat the Elder Wand will pose if Voldemort retrieves it; but having had that conversation, Harry presumably can release Ollivander to another safe house. Eventually, of course, Ollivander is transferred to Auntie Muriel's house, once it is believed that he is sufficiently recovered. The need for Griphook to stay at the cottage becomes clear very shortly as well. Bellatrix' reaction on seeing the Sword of Gryffindor convinces Harry that something Voldemort values very highly is in Bellatrix's vault at Gringotts, almost certainly a Horcrux, so Harry must break in to Gringotts to recover it. A source of inside knowledge about Gringotts is vital to that endeavour, and Griphook is that source.

It should also be noted that, despite being called "safe houses," no house in England at this point can be considered completely safe. The Tonks' house, which was a safe house when Harry and Hagrid visited there on their way to The Burrow as Harry escaped the Dursleys', was not safe enough to protect Ted Tonks, who is on the run from Snatchers when we see him last. The Burrow, also a safe house, falls to Death Eaters immediately after Bill and Fleur's wedding. The only three safe houses which we believe have not seen Death Eater incursions to date are Shell Cottage, Auntie Muriel's home, and Grimmauld Place... and we are not completely sure about the last.