These are the parish registers for 3 parishes that are now part of the city of Mandal, that were for many years part of the same clerical district, which was at times called Halse and at other times Mandal. They include records for the state religion (Lutheran) but also for "dissenters". Many of these registers were microfilmed for the FHL library, and later digitized and made available online through the Norwegian Digital Archives (Digitalarkivet). The Digital Archives make available newer registers that were not part of the Family History Library microfilms.
Some of the registers were consolidated (all parishes in one set of registers) and some were separate by parish, and the different types of events (baptisms, confirmations, marriages and burials) were sometimes organized differently. You may have to check several of the links above to find the set of registers you need to search.
Note that Digitalarkivet includes searchable transcribed records for some of the registers - the transcription appears to be ongoing. The search has limited flexibility and does not appear to support soundex at this time.
FHL film numbers
These may be ordered through the nearest Family History Center.