During the first half of the 20th century Flatonia's prospects increased and decreased according to the national economy and cattle and cotton markets. In 1950 Flatonia had 1,024 residents, 50 businesses, and a wide farm and ranch service area. In the 1960s cotton no longer was a substantial aspect of the area economy; therefore many area farms began to ranch cattle. During that time the population was between 1,000 and 1,500. Interstate 10 (I-10) opened in the 1970s, leading many tourist businesses to move from U.S. Highway 90 to I-10, one mile north of Highway 90. In 1985 Flatonia had six businesses. In 1990 Flatonia had 1,295 residents.