The town was founded with the name of El Zapallar on 25 April 1907, althought the measurement and division of the terrains was properly finished on 2 July 1913. Its progress was slow due to the lack of communications, and began only in 1917, when Juan Godoy opened a precarious bus line that linked El Zapallar with Resistencia, the provincial capital (120 km away).
By 1924 El Zapallar had 5,000 inhabitants and was the head town of the Toba Department. It had a police station, a court, a civil registration, a social club, and mail and telegraph services. That year featured the birth of El Zapallar Agricultural Cattleman Association. The Quijano railroad line also contributed to the growth of the town, by connecting it to Lapachito.
A Development Commission was created by decree of Hipólito Yrigoyen in 1928. In 1934 the town was turned into a municipality, which was re-named General José de San Martín in 1955.
Chapi