James Taylor Gaines, a signer of the Texas Declaration of Independence, was born on November 14, 1776, in Culpeper County, Virginia, the son of Thomas and Susanah (Strother) Gaines and a descendant of the distinguished Pendleton family. He was a double first cousin to United States Army general Edmund Pendleton Gaines, with whom he worked in 1803–04 by order of President Thomas Jefferson to survey lands along the Natchez Trace. He was christened Robert Thomas but changed his name to James around 1810. Gaines operated a Sabine River ferry by 1812. He raised and commanded troops in the Gutiérrez-Magee expedition, an effort to wrest Texas from Spain. Tall, red-haired, and red-faced, he was "Captain Colorado" to the Alabama and Coushatta Indians he commanded. After defeat in San Antonio, Gaines went to Virginia and fought against the British in the War of 1812. In 1819 he bought the long-established ferry on El Camino Real, and with his sons and employees operated the facility over twenty years, bringing (it was said) four-fifths of the colonists across from the United States to Texas. He served as alcalde for the Sabine District of the Municipality of Nacogdoches in 1824, sheriff in Nacogdoches in 1828, and postmaster for years. Beside the ferry, he operated an inn and mercantile store and forwarded mail across the boundary into the United States. He later founded the town of Pendleton on this site.
In 1826–27 Gaines was a decisive leader in the forces opposing Haden Edwards in the Fredonian Rebellion, and by his stand on behalf of the old settlers made enemies who injured his reputation in later years. However, he retained the respect and loyalty of the electorate and represented the Sabine region in Washington-on-the-Brazos in March at the Convention of 1836. Here he served on the drafting committee for the Declaration of Independence, signed the declaration, and helped write the Constitution of the Republic of Texas. In the republic he served as a senator in the Fourth, Fifth, and Sixth congresses, representing Shelby, Sabine, and Harrison counties. In February 1843 Gaines sold his ferry and moved to Nacogdoches, where he led campaigns to obtain annexation for Texas. He soon moved to Bastrop in Central Texas, where he owned and operated a hotel. With news of the California gold rush, his sons Edmund and John B. went with other East Texans along the Gila Trail to the mines to make their fortunes, and James Gaines himself arrived on the steamer Ecuador in San Francisco on August 23, 1850. He was instrumental in imposing law and order in the mine fields and held office for years in Mariposa County. He and his sons discovered the rich Gaines Ledge of gold and established the Mount Gaines Mine, which still exists. Although his sons returned to Texas, Gaines remained at the mine, as his wife had died and he had no home in Texas.
Gaines was married three times. He and his first wife, Isabella Christian of Tennessee, had a daughter; he and his second wife, Katherine Vincent of Indiana, had two sons; he and his third wife, Susanah Norris of the Nacogdoches municipality, had six children. Enemies charged Gaines committed bigamy when he married for the second time, but proof is lacking. Gaines died on November 12, 1856, and is buried near Oakland, California.