Information from 900 years back (written in 1836)
How the name Aclare originated is thus (according to the OS Memoirs of Lance-Corporal Henry Trimble in December 1836) :
In former days there was no bridge at Aclare but a ford with large stepping stones across the river, and when flooded the people had to throw a plank across those stones to get across the opposite side of the river.
In them days there were three brothers of the name of O’Hara. Their place of residence were in three castles, two of which are in this parish and the third in the parish of Achonry, namely Ballyara Castle. The Kilmacteige castles were at Bellaclare and Castle Rock.
The eldest brother was Clare O’Hara who lived in Bellaclare (Belclare) Castle.
The “modern” Aclare Bridge over the River Eignagh
A in Irish is “a ford,” and the Christian name of O’Hara being Clare, A and Clare joined together to make Aclare, being the name and true origin of this market village.
Where's Merrill? 
Rosheen
There’s a History of Sligo by Wood- Martin- similar stories- and Archbishop O’Rourke also wrote a history of Sligo- there were the dispossession in the 1650’s and I think all the local land owners the O’Haras
gathered in the Hamlet of Killure-
Love
M