San Marcos, a city in Texas, USA, is among the oldest inhabited areas (continuous) in the Northern Hemisphere. In fact, evidence gathered by archaeologists would indicate that the city was inhabited for over 10,000 years already. It is also known as "San Marvelous" and the "Hill Country Jewel".

San Marcos has a diverse population of about (72%) are Whites and the rest of the population is composed of African Americans, Native Americans, Asians, Pacific Islanders, Latino/Hispanic, and other races. The largest industry in the city is that of education - with the Texas State University - San Marcos, San Marcos Baptist Academy, Southwest Texas State University, Gary Job Corps Training Center, and other schools serve the area.

San Marcos is home to the San Marcos Springs that gave rise to the San Marcos River - these waters have a diverse ecosystem with several endangered species living in them. Attractions in the area include the Wonder World, Aquarena Springs, LBJ Museum of San Marcos, and Calaboose Museum of African-American History. Visitors can also ride the glass-bottomed boats and cruise on the rivers.