CRH plc (Cement Roadstone Holdings) is an Irish company that initially operated cement plants in the Republic of Ireland, and entered the British Portland cement business with its acquisition of part of the British holdings of Lafarge.

The company began as Cement Limited (informally known as Irish Cement), launched in May 1936 to build two modern cement plants at Drogheda and Limerick, both of which became operational in 1938. Designs, equipment and technical management were provided by FLS. The Irish government and FLS both had substantial holdings, and the company was the exclusive cement producer in the Republic. In 1970 it merged with Roadstone Limited to form CRH, which went public in 1973. The cement operation in Ireland was formally called "Irish Cement".

The company grew internationally initially in aggregates and concrete. In 1995 it began its international cement activities with the purchase of a Polish plant, and from 1999 it began a major acquisition campaign, becoming one of the major cement firms worldwide. The company finally entered the British industry by acquiring three plants that were divested during the merger of Lafarge and Holcim. The British and Irish plants are:

Aberthaw
2015-
Drogheda
1938-1977
Dunbar
2015-
Limerick
1938-
Platin
1972-
Tunstead
2015-

The company is now the largest cement producer in Britain and Ireland. The UK operation is now called Tarmac and uses the Blue Circle logo and brand.

See UK website and Irish website.