In 1956, the government of India effected a comprehensive re-organisation of provincial boundaries, based upon the principle of shared language. Those areas that spoke the Kannada language were thus unified into one state. As a large portion of this new state comprised the territory of Mysore, the name "Mysore" was, at that point of time, retained as the name of the newly created Kannada-speaking province. This state was then renamed Karnataka in 1973.
Thus, the term "Mysore State" or "Old Mysore State" may refer to:
The same territory which functioned as a state within the union of India between 1947 and 1956;
The name of the unified (considerably enlarged) and linguistically homogeneous Kannada-speaking state that was created in 1956, within the union of India. This was renamed Karnataka in 1973.