Many free blacks came to Houston after the civil war. Not receiving the support of the incumbent white population, they formed their own social and economic networks. Black residents constituted about twenty percent of the Houston citizenry throughout the rest of the nineteenth century. Investment and development of railroads serving Houston increased the transportation options for freight and passengers, while greatly increasing the number of jobs. The City limits extended to an area north of Buffalo Bayou after the Civil War. Houston continued as an important business, social, and economic center of Texas, while establishing the first State Fair starting in 1870 and continuing through 1878.