Why is St James' Park in London officially called St James's Park?

Answer 1

Three palaces border this gloriously green park: the ancient Palace of Westminster, now the Houses of Parliament; the Tudor St. James's Palace; and Buckingham Palace. Acclaimed as the most royal of the royal parks, Saint James's Park is also London's smallest, most ornamental park, as well as the oldest; it was acquired by Henry VIII in 1532 for a deer park. Henry VIII built the palace next to the park, which was used for hunting only (dueling and sword fights were forbidden). James I improved the land and installed an aviary and zoo, and Charles II laid out formal gardens. St. James's Park makes a spectacular frame for the towers of Westminster and Victoria -- especially at night, when the illuminated fountains play and the skyline beyond the trees looks like a floating fairyland.

Answer 2

It's called St. James's Park rather than St. James' park because that was the correct spelling at the time the park was named. The newer spelling, the one you used, will be accepted soon as most people use it, but when it was named, the older form was considered the only correct one.

St. James and King James were two very different people. Why St. James instead of St. George, Britain's patron, I have no idea.

Answer 3

The apostrophe goes after the final s when the word is plural. St James is singular, so the correct form is St James's. It's pronounced "St Jameziz" wheras St James' would be pronounced the same as St James. Hope this makes sense.