Coolsaragh (locally [ˌkulˈsɑrə], from Irish Cúil Sáráin, meaning 'Sárán's recess'[2]) is a townland lying within the civil parish of Kilcronaghan, County Londonderry, Northern Ireland.

[3] Coolsaragh, despite the various different spellings, many of which contain erroneous letters, such as h for r and f for s, appears to derive from something like Culsaran or Coolsaran.

The loss of the n at the end of the word, whilst not common in Irish placenames, has occasionally occurred elsewhere.

[2] The "saran" could possibly be derived from the Irish word során, which means "wireworm", a kind of insect that is a considerable pest for farmers, eating the roots of tuberous plants.

The personal name Sárán is used in the townlands of Kilsaran and Tisaran, and was the name of several saints and an early king of Ulster, and is quite possibly the meaning of "saran" in Culsaran or Coolsaran.