My ancestor Robert Robertson Graham, died in Matamoros, Mexico March 24, 1849. I have a letter he wrote in 1846 from Mexico. I have found no enlistment information for him at NARA. From a close reading of his letter, I believe he was regular Army, navy or merchant marine already serving before the recruitment for the Mexican war began. He was born abt 1820 in North Argyle, Washington County, NY. I'm seeking the help of anyone who may have access to documents or books listing enlistments, pensions or land bounty records.
Thank you for your help.