The Erriff Fishery and Aasleagh Lodge were formerly part of the Marquis of Sligo Estate. The original Lodge was a very large Victorian style country house. It was photographed as part of the Laurence collection of photographs of the area in circa 1907. Like many of the big county houses in Ireland it was burned down in 1921. It was rebuilt but on a smaller scale in 1926. The East wing of the Lodge was demolished with only part of the ground floor retained as a Drawing Room.

There appears to be relatively little fishing done on the fishery during the Second World War. One of the great fishers on the Fishery was Mrs. Alice March who leased the Lodge and Fishery from Lord Sligo, Westport Estate from 1951 to 1969. Mrs. Marsh was an excellent fly angler and there are records of her catching several Spring salmon in a day including three fish from the Holly Pool one morning before Breakfast. Claud Hunt was Manager of the Fishery at the time and he resided in Aasleagh Cottage.

Mrs. March died in 1969 and is buried in the nearby Churchyard overlooking her beloved Killary harbour. The Lodge and Fishery was then bought by Lord Brabourne of the Knatchbull Family who were related to Lord Sligo in Westport. The Drawing Room and front porch were demolished during this period. Guest fishers at the time included Lord Louis Mountbatten of Burma and Graham Hill the famous racing driver from the U.K.

The Lodge and Fishery was purchased by the State in 1981 after the tragic death of Lord Mountbatten and Nicholas Knatchbull when their fishing boat was blown up by the I.R.A. in Mullaghmore, Co. Sligo when staying in Classiebawn Castle. The Lodge and Fishery were then purchased by the State in conjunction with the Central Fisheries Board and are currently managed by Inland Fisheries Ireland (formerly the CFB and Regional Fisheries Boards).