Kreisarchiv Nordfriesland: https://www.nordfriesland.de/Quicknavigation/Suchergebnis/index.php?La=1&NavID=2271.7&object=med,2271.390.1.PDF
Partial book catalog of the archives: https://www.nordfriesland.de/PDF/Buchkatalog_2013.PDF?ObjSvrID=2271&ObjID=1240&ObjLa=1&Ext=PDF&WTR=1&_ts=1369204796
An inventory of the Kreisarchivs Nordfriesland (KANFK) is available at this link:
https://www.nordfriesland.de/media/custom/45_6137_1.PDF?1229352055/
A partial translation of some items of interest follows:
A1 contains the official accounts and appendices of the Husum office from the years 1706-1858 (with gaps). These are duplicates of the accounts available in the state archive.
A2, Landschaftsarchiv Eiderstedt, includes 3rd Schleswig dike band, parishes as political communities, water solutions and Holländer Mobilien-Brandgilde [Dutch Mobile Fire Guild]. The inventory was created in 1932, some files were added in later years. More recent files from the communities form new holdings, but the files of a community are summarized in a single inventory. The focus of the Eidersted files is on legal matters, dikes, Koog and water solutions, militaria, the town of Tönning and the church registers of the individual parishes, which are available here in copies. The period essentially covers the 16th to 19th centuries. The documents of the Dutch Fire Guild include, among other things, inventories and estimates of the fire damage that occurred from the middle of the 18th century to the beginning of the 20th century. In total, there are 3,895 documents and files, some of which only cover one sheet each.
A3, the island archive of Föhr, is also a collection that is made up of several provenances. It contains files of state origin from the time of the Danish administration up to 1867 (Bailiff's Office, Birkvogtei, Osterland- and Westerlandföhr regions, Court Bailiwick, etc.), of state origin from the Prussian administration since 1867 (Bailiff's Office, Beach Office, etc.) and of municipal origin (Osterlandföhr and Westerlandföhr offices, Wyk town). The most extensive archive is that of the town of Wyk with around 3,800 files from the period 1706-1974. Numerous files about the town of Wyk can also be found in the bailiwick's collection. Particularly extensive in this collection are the bankruptcy, liquidation, auction, inheritance and division files from the 18th and 19th centuries.
A4, Strandvogteibezirk 7, Süderoog, contains only three files, but among them is the list of ships stranded on Süderoog from 1798-1922.