The Union Land Company was founded in New York in December 1830 by James Prentiss, his brother Henry Bowdoin Prentiss, and James Prentiss's son James Henry for the purpose of colonizing lands in Texas in the grants of Joseph Vehlein, David G. Burnet, and Lorenzo de Zavala. The company bought scrip for twenty-eight leagues (123,995 acres) from the Galveston Bay and Texas Land Company. Henry A. Green, a clerk of James Prentiss, and José Antonio Mexía were agents of the company. In January 1831 the Union Land Company sent fifty emigrants to Texas on the schooner Crescent, and in April 1831 forty-seven more arrived on board the Climax, which was wrecked at the entrance to Galveston Bay. These ninety-seven people formed the twenty-eight families required to possess the twenty-eight leagues. The principal agent of the company in Texas was Henry Prentiss, who arrived in Texas with the settlers on board the Crescent and established a mercantile business in Anahuac. This he left in the hands of George M. Patrick, who had to leave Anahuac on March 11, 1833, because of business stagnation. Before the state-appointed land commissioner of Texas, José Francisco Madero, could issue titles to the twenty-eight families who wanted to settle on the Trinity River, however, he was arrested by an order of John Davis Bradburn for violating the Law of April 6, 1830, designed to stop the flood of immigration from the United States. The Union Land Company rented a tract of land nearby for the use of the settlers.
In May 1834 Henry Prentiss sold his interest in the Union Land Company to his brother James. As no other person had ever acquired a title or shares of the company, the entire interest of the company, both legal and equitable, became vested in James Prentiss. In 1842 Prentiss formed a partnership with Gilbert L. Thompson. That year the company, represented by Richard S. Coxe, a trustee, claimed to have spent $428,383.18 between 1831 and 1834 in order to fulfill its purpose. It is difficult to believe, however, that the Union Land Company would have spent more than three times as much as the Galveston Bay and Texas Land Company had invested in its own efforts to colonize the same land grants. According to Henry B. Prentiss, the Union Land Company had expenses in Texas of about $560 and assets of approximately $1,290. The company was most likely only a land speculation enterprise for James Prentiss and his family. John Thomson Mason, an agent of the Galveston Bay and Texas Land Company, wrote a report to his company in March 1834 stating that under the name of the Galveston Company James and Henry Prentiss had caused great alarm by their speculations. Although the United States and Mexican Claims Commission regarded the claims of the Union Land Company as invalid, it awarded the company $58,879.10 in 1851.