The Mercer colony was located in north central Texas east and south of the Peters colony. It lay roughly between the Brazos and Sabine rivers, north from Waco to McKinney in Collin County, skirting to the south and east of what is now the Dallas metropolitan area. Its boundaries encompassed portions of eighteen future Texas counties. The colony grew out of a statute enacted by the Texas Congress on February 4, 1841, restoring the Mexican policy of granting empresario contracts to persons who promised to settle individuals and families on the unclaimed public land of the republic. In spite of growing opposition to such contracts, President Sam Houston granted Charles Fenton Mercer a contract to settle at least 100 families a year for five years, beginning on January 29, 1844. Mercer soon organized a company, the Texas Association, to advertise and promote colonization, and sold shares at $500 each to investors in Virginia and Florida as well as in Texas.
The work of colonization was impeded by the fact that various politicians, land speculators, and squatters, all eager to supplant the empresario system with the Anglo-American land system, questioned both the wisdom and the legality of granting away the republic's vast public lands without financial gain. Mercer himself was also unpopular, for he was known as an abolitionist, a speculator, a monopolist, and an opponent of free immigration for Anglo-Americans. One day after the execution of Mercer's contract the Congress of the republic passed, over President Houston's veto, a statute outlawing colonization contracts. Congressional resentment culminated in an investigation during 1844–45 of Mercer's contract and his efforts to fulfill its terms. Meanwhile, squatters moved into the Mercer survey and denied the claims of settlers who held Mercer colony certificates. Settlers also discovered land speculators and holders of bounty and headright certificates already claiming the land for which they had contracted, and Mercer's surveyors reported that Robertson County, joining the colony on the south, was sending its surveyors into the limits of the empresario grant and claiming the land they surveyed. Finally, Mercer surveyors and settlers clashed with both civil and military forces when they attempted to penetrate that portion of the grant lying west of the Trinity River.
Mercer's association initially offered only 160 acres to families and eighty acres to single men. The fact that the adjacent Peters colony promoters were offering 320 acres (later 640) to families diverted many newcomers to that colony before Mercer finally matched the offer. Nevertheless, by the end of the first year of the contract, more than 100 families had complied with the requirements and received land certificates. After the Convention of 1845 instructed the new state of Texas to begin legal proceedings against all colony contracts, Governor Albert C. Horton instituted suit on October 11, 1846, against Mercer and the Texas Association in the district court of Navarro County. Judge Robert E. B. Baylor of the Third Judicial District declared the contract between Mercer and Houston null and void, but the Texas Supreme Court subsequently upheld the legality of the contract. On February 2, 1850, the Texas legislature, seeking to quiet the confusion within the colony, guaranteed all land claims made by settlers in the Mercer colony before October 25, 1848. By virtue of this legislation, 1,255 land certificates were recorded in the General Land Office, but the measure failed to adjust all conflicting land claims, some of which were in process of litigation as late as 1936. In the face of these developments, and in hope of protecting the investments of his associates in his Texas project, Mercer severed all connection with the grant on February 27, 1852, by assigning his interest in the Texas Association to George Hancock of Louisville, Kentucky.
Although settlers recruited by Mercer and the Texas Association were ultimately granted the lands they had settled on, the state of Texas steadfastly refused to legalize any claims of the association itself. The state would not allow the association to sue in state courts and defended with vigor against all claims that it brought. The commissioner of the General Land Office threw open for sale the public lands within the Mercer grant, and on March 6, 1875, the chief agent of the association filed an injunction in the United States circuit court at Austin, demanding that the land titles of the association be legalized whether within the area of the Mercer colony grant or elsewhere within the public domain of Texas. The United States Supreme Court settled the issue in 1883 by denying all compensation owed the association that was based on the original empresario contract.