San Carlos (Spanish pronunciation: [saŋ ˈkaɾlos]) is the capital city of the municipality of San Carlos and of the Río San Juan Department of Nicaragua.
The city proper has a population of roughly 17,000, while the city and surrounding communities (Comarcas) contain a population of 52,055 (2022 estimate). San Carlos is positioned on the confluence of Lake Nicaragua and the San Juan River. The Solentiname Islands in Lake Nicaragua are part of the Municipality of San Carlos.
The municipality is divided into the following comarcas:
San Carlos is twinned with:
11°08′N 84°47′W / 11.133°N 84.783°W / 11.133; -84.783