Thompson's Islands
San Marcos, Hays County, Texas
Marker Inscription
William A. Thompson brought his family and slaves to Texas from Louisiana in 1850. They established plantations in Caldwell and Hays counties. With slave labor, the family built a mill on the San Marcos River near this site. Construction and operation of the mill resulted in the creation of three land masses in the river channel which became known as Thompson's Islands. The land remained in the family for generations, and the mill, which provided power for local lumber operations and a cotton gin, became an important element in the area's economy.
Erected by Texas Historical Commission
The Story
William A. Thompson moved his family and the people he enslaved from Louisiana to Texas in 1850, establishing plantations in Caldwell and Hays counties. Enslaved laborers built a mill on the San Marcos River whose construction reshaped the channel into three small islands still called Thompson's Islands. The mill powered local lumbering and a cotton gin, anchoring the area's antebellum economy for generations.
Why it matters
The site is a candid reminder that the prosperity of antebellum Texas rested on enslaved labor, whose work literally reshaped the land it stood on.
Own a business near here? Add it to the map.
Related people
- · William A. Thompson
Themes & tags
Nearby & related markers
Thompson's Island Homeplace
San Marcos, TX
In 1850 Dr. William Alexander Thompson struck an agreement with his neighbors to harness the San Marcos River, and he and his sons used enslaved laborers to build a gristmill, sawmill, and cotton gin. The channels dug for the waterwheel created the parcels known as "Thompson Islands." The family ran the mills until 1911, and the arrival of electricity in 1942 finally ended the site's dependence on water power.
Ulysses Cephas
San Marcos, TX
Born in San Marcos in 1884 to formerly enslaved parents, Ulysses "Boots" Cephas learned the blacksmith's trade from his father and grew into one of the county's most respected craftsmen, prized for his skill at shoeing horses and building wagons and farm tools. He owned his own shop and gave back to his community as a church member and organizer of the San Marcos Independent Band. His life traces one family's path from bondage to skilled independence in a single generation.
Kyle Depot
Kyle, TX
When the International and Great Northern Railroad pushed south from Austin toward San Antonio in 1880, the Kyle and Moore families donated 200 acres for a roadbed, depot, and townsite, and a canvas tent quickly gave way to a permanent station. For decades the depot was the beating heart of Kyle — shipping cotton, cattle, and lumber, carrying the mail and Western Union telegrams, and moving nearly everyone who traveled. Its waiting rooms and entrances were segregated in keeping with the Jim Crow laws of the era, and after an 1916 fire the depot was rebuilt on the same site in 1917.
Farmers Union Gin Company
San Marcos, TX
A group of local farmers bought this San Marcos site in 1908 and, under the leadership of Oscar Calvin Smith, established the Farmers Union Gin Company—the first industrial plant of its size in town. The surviving brick gin house dates to 1911, replacing an earlier structure lost to fire. For more than half a century the gin was a linchpin of the area's cotton economy, running until 1966.