Dotted all around the countryside surrounding Claremorris much evidence can be found which indicates that this area has been inhabited by humans for many centuries.
One of the best historical sites in this area is probably Ballinasmalla Abbey but there are also many others, each with many stories attached. At the ruins of the abbey in Ballinasmalla there are two examples of inscribed stone as well as the ruins of the 13th century chapel and the Penal church.
The Seconday school in Claremorris was once Claremount House and has in the past been home to the Kirwan family and the infamous Dennis Browne MP, Peace Commissioner and High Sheriff of Mayo. Many stories exist about the notorious Dennis Browne who was much feared by the people of Claremorris because he was known to ruthlessly hang people for fairly minor crimes. At Claremount House there are two very interesting historical features - one is a cone shaped hut and the other a souterrain. The hut is located to the front of the house and there are many theories about it's function. One theory suggests that it was an early form of Turkish bath and another suggests that it was used for storing ammunition. The souterrain runs from the western wall of the kitchen in the basement of the house to a field in Ardroe. It's purpose is also unknown but it is thought that it may have been a means of escape for the occupants of the house in time of attack.
On the banks of the River Robe, three and a half miles from Claremorris lie the ruins of Castlemacgarrett Old. It was built in the 13th century and was once the home of the famous Browne family of Claremorris. The castle was unique for its period because it was built in a three tier fashion with a central stairway leading to each individual floor, with connecting stairs, instead of the usual single spiral corner stairway. There is currently a preservation order and a restoration project scheduled for the not too distant future.
The new Castlemacgarret house was built in 1694 by Geoffrey Browne because the old castle was rapidly disintegrating and becoming unsafe. Lord Oranmore and Browne extended the house in the early part of this century and did much to enhance the entire residence. Although today it is a private nursing home run by the Sisters of Our Lady of Apostles, a lot of the former grandeur of the house remains.
There are several crannogs in this area indicating ancient settlements here. There is one in Rooskeybeg, one in Drumady Lake and two possible crannogs in Mayfield Lake.
In Tawnagh there is a very good example of a ringfort or a rath and there is also a children's burial ground in this townland which is on unconsecrated ground and was used for babies who died before being baptised. This can be reached by taking the Kiltimagh road as far as the crossroads where you turn left, over the railway bridge and the ringfort is a ten minute walk through the field just after the little bridge over a stream on the left.