Hewetson was born in Thomastown, County Kilkenny, Ireland in 1797, the son of Patrick and Honora (née Hoyne).
[1] Already set on moving from the United States to Mexico, Hewetson encountered Stephen F. Austin in St. Louis, Missouri.
[1] Hewetson parted ways with Austin at San Antonio de Béxar and continued further on into Mexico, eventually settling at Saltillo and Monclova in Coahuila.
The next year, Power and Hewetson requested more land and their holdings were extended west to the Nueces River, which included Nuestra Señora del Refugio Mission.
Ownership disputes with other empresarios forced Power and Hewetson to cede some land east of the Guadalupe River and the new eastern boundary was drawn at Coleto Creek.