Placenames occur with various spellings that have evolved over time, some with anglicization from the original gaelic. The spellings in the index will reflect those given by the 1st Ordinance Survey of Scotland in 1862. Many locations no longer exist or are merely ruins in present day. Those locations will use spellings of earlier maps.
The boundaries of the parishes of Perthshire were rather piecemeal prior to 1889, so parish records would not reflect that which that is now commonly known. The locations within the index attempt to reflect the boundaries in early 1900. Corrections will be made as work progresses. The 1841 census lists locations in the pre 1889 boundaries which can make research confusing.