The first settlers arrived in this area in 1846 for the black fertile prairie soil of North Texas where cotton was “King”. Between 1850 and 1902, two settlements existed. One community, two miles south of the present town, was called Rock Hill. The second community, one mile north, was called Richland. The development of these small communities was expedited in 1876 when County Courts ordered small tracks of land to be established for quick sale. These tracts, each approximately 160 acres in size, were sold for $3.50 per acre. Dr. A. T. Bryant of McKinney purchased one of the tracts, which later became the geographic nucleus for the Town of Prosper.
The establishment of the St. Louis & San Francisco Railroad in March of 1902 created the change that forced the communities of Rock Hill and Richland to merge forming the Town of Prosper. For years, Prosper was the central stop for the railroad between Dallas and Sherman. When community officials applied for a Post Office with the name “Richland”, they were informed that city name was already taken. Postmaster B.J. Naugle asked for an alternative name and J.C. Slaughter suggested the name Prosper, because crops that year had been very prosperous.