Rosario, officially the Municipality of Rosario, is a 1st class municipality in the province of Cavite, Philippines. According to the 2020 census, it h…Rosario, officially the Municipality of Rosario, is a 1st class municipality in the province of Cavite, Philippines. According to the 2020 census, it has a population of 110,807 people. Formerly known as Salinas, Rosario has an area of 5.6 square kilometers, making it the most densely populated city/municipality in Cavite at 16,473 per km². With the continuous expansion of Metro Manila, the municipality is now included in Manila conurbation which reaches Lipa, Batangas in its southernmost part. It is accessible by land and water transportation.