This is the third and (barring further significant discoveries) the final part of my index, the first and second parts of which were published in Recusant History in October 1982 (nos. 1–177) and May 1998 (nos. 178–300). In Part II, for reasons of space and cost, I omitted, unless there was more to report on them, houses mentioned in my Secret Hiding-Places (1989) but not included in Part I. For reference and analysis, however, it is inconvenient to have a numbered list and a book, each including houses not in the other; and in any case there is now more to report on many of these houses. The one hundred houses in Part III (nos. 301–400) therefore include all sixty-nine of those that were mentioned, however briefly, in Hodgetts 1989 and were not included in Parts I or II. Among them is Scotney Old Castle in Kent (no. 320), which is one of only ten houses in the country where there is a surviving hide mentioned in an Elizabethan or Stuart account of a search. Forty-eight of the hundred were in Granville Squiers’ Secret Hiding-Places (1933).