The history of local government in Yorkshire is unique and complex. Yorkshire is the largest historic English county and consists of a diverse mix of urban and rural development with a heritage in agriculture, manufacturing, and mining. After a long period of very little change, it has been subject to a number of significant reforms of local government structures in modern times, some of which were controversial. The most significant of these was the Local Government Act 1972 and the 1990s UK local government reform. It currently corresponds to several counties and districts and is mostly contained within the Yorkshire and the Humber region.