The Old Stone Fort is the modern name of a historic building, called La Casa Piedra by the Spanish. It was the first mercantile house and a frequent seat of civil government in early Nacogdoches. In 1779 Antonio Gil Ibarvo laid out the town near the intersection of the Old San Antonio Road and La Calle del Norte and built a stone house to use in the trading business. It was constructed of the native iron ore that occurs in the area abundantly. The interior walls were made of ten-by-fourteen-inch sun-dried adobe blocks. Hand-hewn black walnut was used for sills and casements. The structure measured seventy feet along the Old San Antonio Road and twenty-three feet along Fredonia Street, as this lateral street was later called.