Lord Howard of Glossop sold part of the estate to the county council and to a mining company in the late 1930s and early 1940s.

Loch Thom and the Greenock cut provide easy walks in a context of industrial history, and the Collegiate church and Castle Semple are of interest to historians of an earlier era.

Clyde Muirshiel offers year-round instructor led activities include sailing, kayaking, canoeing and raft building on the shallow inland Castle Semple Loch as well as land activities such as archery, mountain biking, hill walking, orienteering, navigation and first aid.

[4] The Sustrans Lochwinnoch Loop Line cycle track runs through the Castle Semple Loch visitors centre.

Castle Semple was a Collegiate church, which means that it was administered and served by a college of canons or prebendaries, presided over by a dean or provost.

The aqueduct supplied both a dependable flow and a good quality of water to the town for both domestic and business purposes.

[7] Seams of Baryte minerals were found in three gullies about 2 kilometres (1.2 mi) north of Hill of Stake, cut into the slope by tributaries of the River Calder, Renfrewshire.

Small-scale open cast mining of the baryte began around the mid 18th century, with horizontal tunnels or adits cut to follow the seams of the mineral.

A track was formed running around 4 kilometres (2.5 mi) downhill to a grinding mill sited on the River Calder, where the mineral was dressed or processed.

Stables and houses for the workers were built adjacent to the mill, and a bridge crossing the river connected by a lane down to Lochwinnoch.

Up to this stage there was no electricity at the mine, and minerals were transported in wagons on rails, moved to the surface by human or horse power.

At this time up to 48 people from Lochwinnoch and Kilbirnie worked at the mine, including 11 skilled miners, each with an assistant, as well as maintenance and surface workers.

[8] When the country park was formed, the Muirshiel Visitor Centre was built a short distance downhill from the pre-1920 site of the mine.