The group's leader, Warren Jeffs, is serving life in prison after being convicted of sexually assaulting two girls he took as child brides.
The Texas Department of Public Safety says its agents took possession of the secluded property near Eldorado on Thursday. In a statement, DPS says authorities were helping the remaining eight adults living on the ranch leave and to do an inventory.
A judge in January ordered the forfeiture of the Yearning For Zion Ranch, which was owned by the Fundamentalist Church of Jesus Christ of Latter Day Saints.
The state sought to seize the property over allegations of mismanagement by Jeffs.