The following is a list of sovereign states and territories where Tamil is an official or language of government.
Historical map of Chola Kingdom where Tamil was the language of administration.
Tamil is one of the oldest language and 15th most spoken language in the world and which gave birth to new languages such as Malayalam in 15th Century and the first language to be declare as the classical language of India. Tamil language speakers makes approximately 1% of the world population. Tamil was one of the dominant language of trade during the pre-colonial era by people like Ainnurruvar and such as Tamil inscriptions and coins found on many parts of Asia and Africa such as on China, Cambodia, Egypt and Indonesia.
During 18th Century, the British and French rules brought the Tamils to many parts of Asia and Africa which makes many countries with significant Tamil speakers and cultural impact such as there are more than 1,000,000 speakers of Tamil language in the Malaysia itself.
Sovereign states 
Dependent entities where Tamil is an official language 
Distribution of Tamil speakers in Indian Subcontinent.
Partially recognized and unrecognized states/territories 
Countries where Tamil is used and has cultural impact but not official 
Mauritius 100 Rupees Currency Showing Tamil Script Along With English And Hindi.
There are also claims to make Tamil an official language of India and the UN.
See also