The establishment of America's transcontinental rail lines securely linked California to the rest of the country, and the far-reaching transportation systems that grew out of them during the century that followed contributed to the state's social, political, and economic development. When California was admitted as a state to the United States in 1850, and for nearly two decades thereafter, it was in many ways isolated, an outpost on the Pacific, until the first transcontinental railroad was completed in 1869.