John Reagen Baker was an adventurer-soldier of early Texas who fought in Mexico in 1840 to win freedom for the unsuccessful Republic of Rio Grande. He was elected sheriff of Refugio County and organized a company of minutemen. In 1842 he fought against three Mexican raids into Texas, then took part in the disastrous Somervell and Mier expeditions into Mexico, during which he was wounded. He later returned to Texas and entered the mercantile business. His wife was Avis Brown.