The York Rite is one of the two great systems of additional Masonic degrees, and the most common misunderstanding of it is to picture a single body: it is in fact a grouping of separate organisations worked in sequence.
Three bodies, one journey
The York Rite comprises several distinct organisations offering degrees that continue the Masonic journey beyond the three degrees of the craft lodge: the Royal Arch chapters, the Cryptic councils, and, in most jurisdictions, the Commanderies of Knights Templar, each governed separately and conferring its own degrees. A member proceeds through them in order, and membership requires that he first be a Master Mason. The Templar bodies are distinctive in requiring a Christian profession, where the craft lodge does not.
An American assembling of English degrees
The degrees themselves grew from older workings in England, and were organised into their present grouping, particularly in the United States, during the nineteenth century, which is why the name York, referring to the legendary early history of English Masonry, attaches to a system largely arranged in America. It stands alongside the Scottish Rite as one of the two main routes for additional Masonic degrees, the two differing in structure and emphasis rather than in rank.