All states have a Section 218 agreement with the federal government's Social Security Administration. For more information see Chapter 10 of this Social Security Handbook. This July 8, 2004 Social Security Handbook chapter 10, section 1002.1 defines what is an interstate instrumentality.
Miles City is a city in and the county seat of Custer County, Montana, United States. The population was 8,123 at the 2010 census. After the Battle of the Little Bighorn in 1876, the U.S. Army created forts in eastern Montana, including one where the north-flowing Tongue River flowed into the east-flowing Yellowstone River. The first fort was known as the Tongue River Cantonment or the Tongue River Barracks and was founded on August 27, 1876. A second, permanent fort was constructed on higher ground two miles to the west of the mouth of the Tongue and this became Fort Keogh.
Bozeman is a city in and the county seat of Gallatin County, Montana, United States, in the southwestern part of the state. The 2010 census put Bozeman's population at 37,280 and the 2015 census estimate put the population at 43,405 making it the fourth largest city in the state. It is the principal city of the Bozeman, MT Micropolitan Statistical Area, consisting of all of Gallatin County with a population of 97,304. It is the largest Micropolitan Statistical Area in Montana and is the third largest of all of Montanaâs statistical areas.