harry potter - Do wizards need to know the destination before creating a portkey?

I know the following

Based on the Portkey writing on Pottermore:

• Almost any object can be made into a Portkey.


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  Portkeys can be used to travel almost any distance.

  
  

  
  

  Almost any inanimate object can be turned into a Portkey. Once bewitched, the object will transport anyone who grasps it to a pre-arranged destination. A Portkey may also be enchanted to transport the grasper (or graspers) only at a given time.

  
  

  
  


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  A Portkey is made with the spell Portus

  
  

  
  

  He [Dumbledore] walked away from the pool to the place where the golden wizard's head lay on the floor. He pointed his wand at it and the muttered, ‘Portus.’ The head glowed blue and trembled noisily against the wooden floor for a few seconds, then became still once more. OotP, Chapter 36

  
  

  Dumbledore was now rummaging in a cupboard behind Harry and Ron. He emerged from it carrying a blackened old kettle, which he placed carefully upon his desk. He raised his wand and murmured “Portus”; for a moment the kettle trembled, glowing with an odd blue light, then it quivered to a rest, as solidly black as ever. OotP, Chapter 22

  
  
  

  
  


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  The making of Portkey is regulated by the Ministry.

  
  


• The Ministry cannot detect the making of an unauthorized Portkey.
  

  
  

  ‘Now see here, Dumbledore!’ said Fudge, as Dumbledore picked up the head and walked back to Harry carrying it. ‘You haven't got authorization for that Portkey! You can't do things like that right in front of the Minister for Magic, you – you - Ootp, Chapter 36

  
  

  
  

The question is how much of the destination does the maker of the Portkey need to know about? I.E. Could a wizard who has never been out of Godric's Hollow create a Portkey to New York?

Also, I remember something about the "other half" of the Portkey at destination... can't find any quotes or evidence, so I may just be making things up. This would obviously mean that the maker would have to visit the destination. But this quote from QTtA suggets otherwise

"While there have been no proven referee slayings since [1357], there have been several incidences of broom-tampering over the centuries, the most dangerous being the transformation of the referee's broom into a Portkey, so that he or she is whisked away from the match halfway through and turns up months later in the Sahara Desert."

Related: How and when was the statue head Portkey to Hogwarts set up?

Related: Why is the usage of a Portkey controlled while apparition is free?

Answer

The basic answer to your question is:

Yes, wizards do need to know the destination.

Dumbledore had to know where he was sending Harry/the Weasley children in both the examples you mentioned. He intended to send them from his office to Grimmauld Place in the first instance and to send Harry from the Ministry to his office in the second. Barty Crouch Junior needed to know the destination for the Twizard Cup for it to successfully take Harry (and Cedric) to the graveyard. And the Ministry Portkeys used for the Quidditch World Cup clearly all had the same destination, which was set by Ministry officials in advance. You've got to know where the Portkey you're creating is going for it to do anything.

However, the question seems to asking whether the Portkey-creator needs something more than intent. To that part of the question I'd say:

No, you don't need to have an intimate knowledge of a location to create a Portkey that leads there.

I don't have much Portkey-specific information for this since the books don't go into the process for creating Portkeys in great detail (apart from telling us that the spell used is Portus). However, I can draw some informed assumptions based on the Portkeys that feature in the books and by making parallels to other forms of magical transportation.

Firstly, Barty Crouch Junior appears to have never visited the Little Hangelton cemetery and yet is able to successfully create a Portkey to that location. His account of his recruitment implies as much.

[Voldemort] needed me. He arrived at our house near midnight...Wormtail and I did it. We had prepared the Polyjuice Potion beforehand. We journeyed to his house. Moody put up a struggle...Then I packed up Moody's clothes and Dark detectors, put them in the trunk with Moody, and set off for Hogwarts.

Goblet of Fire, Chapter 35, Veritaserum

Crouch's account heavily implies that he went from his own house straight to Moody's house and from Moody's house straight to Hogwarts. Every indication is that Crouch was able to successfully create a Portkey to Little Hangelton despite never having been there and therefore (presumably) not having much of a picture in his mind's eye of what the Little Hangelton cemetery looked like. All he needed to know is where he wanted to send it.

Secondly, I'd draw a comparison with Apparating. In Apparition, what matters is that you concentrate hard on your destination of choice, wherever that happens to be.

"The important things to remember when Apparating are the three Ds!" said Twycross. "Destination, Determination, Deliberation! Step one: fix your mind firmly upon the desired destination," said Twycross. "In this case, the interior of your hoop...Step two," said Twycross, "focus your determination to occupy the visualised space! Let your yearning to enter it flood from your mind to every particle in your body!"

Half-Blood Prince, Chapter 18, Birthday Surprises

Harry, Ron and Hermione Apparate to a variety of places during the final book, many of which (Godric's Hollow, for example) they've never been to before. I would not be surprised if creating a Portkey involved focusing intently upon a particular destination, even if you yourself didn't necessarily know much about the destination in question. What matters is determination to set a particular destination.

Thirdly, Harry successfully (if inadvertently) manages to travel to Knockturn Alley in Chamber of Secrets via Floopowder despite not even knowing that it exists.

In conclusion, you do need to know the destination to make a Portkey but you don't need to have travelled to that destination before or indeed even be that familiar with it. So yes, theoretically, your Godric's Hollow resident could make a Portkey to New York (although the international travel involved may make getting Ministry of Magic clearance more difficult!).