Sebastian C. Adams Jr., arrived in Oregon in 1850. He was known as a teacher and land surveyor. Adams married Martha McBride on February 6, 1851, in Yamhill County.
In 1854 Sebastian C. Adams was hired by William T. Newby to plat out a town grid in exchange for title to half a block of the new city. McMinnville was platted in May 1856, though it was not recorded in the county clerk’s office in Lafayette until July 1865, even though Newby received his U.S. patent in October 1858.
Sebastian Adams was elected Yamhill County Clerk in 1862; he was elected to the Territorial Senate where he served for four years. Sebastian moved to Salem and was a teacher at Salem's First Christian Church for many years until the death of his wife Martha in 1882.