gsr’s answer is a bit misleading and the diagram in the article is not entirely clear.
The 6.4 metres (21 feet) mentioned by gsr is from the Hog Line to the “Button” (the centre of the “House”) at the distant end. The distance from the Hog Line at the delivery end (by which the stone must be released) to the Button is in fact 93 feet (about 24.4 metres). The House is twelve feet in diameter (so has a radius of six feet) meaning it is 87 feet (25.6m) from the Hog Line to the front edge of the House.