The SPP region lies within the Eastern Interconnection in the central Southern United States, serving all of the states of Kansas and Oklahoma, and portions of New Mexico, Texas, Arkansas, Louisiana, Missouri, South Dakota, North Dakota, Montana, Minnesota, Iowa, Wyoming, and Nebraska. SPP members include investor-owned utilities, municipal systems, generation and transmission cooperatives, state authorities, independent power producers, and power marketers. SPP has many of the high voltage direct current (DC) ties which connect the Eastern interconnection to the Western Interconnection and both of the DC ties to ERCOT Texas Interconnection.