Cádiz is a province of southern Spain, in the southwestern part of the autonomous community of Andalusia. It is the southernmost part of mainland Spain, as well as the southernmost part of continental Europe.

It is bordered by the Spanish provinces of Huelva, Seville, and Málaga, as well as the Atlantic Ocean, the Mediterranean Sea, the Strait of Gibraltar and the British overseas territory of Gibraltar. Its area is 7,385 square kilometres (2,851 sq mi).

Its capital is the city of Cádiz, which has a population of 114,244. As of 2021, the largest city is Jerez de la Frontera with 212,801 inhabitants. Algeciras, which surpassed Cádiz with 122,982 inhabitants is the second most populated city. The entire province had a population of 1,245,960 (as of 2021), of whom about 600,000 live in the Bay of Cádiz area (including Jerez), making it the third most populous province in Andalusia. Its population density is 167.93 per square kilometre.