Cottle received a league of land at the headwaters of the Lavaca River near Gonzales on September 12, 1832.
When Mexican troops arrived south of Gonzales in September 1835, Cottle was one of the messengers sent to gather reinforcements.
He enlisted in the Gonzales Ranging Company under Lt. George C. Kimbell on February 24, 1836, and rode with thirty-two others to the Alamo on March 1, 1836.
Cottle was killed on March 6, 1836, at the battle of the Alamo, alongside his brother-in-law, Thomas Jackson.
His twin sons Thomas Jackson Cottle (named after George's brother-in-law who also died in the Alamo) and George Washington Cottle (Junior) were born March 31, 1836, just 25 days after their father died in the Battle of the Alamo.