Crossword puzzle clue "state of agreement"

Start of an agreement that's not really an agreement

Illinois, Indiana, Iowa, Michigan, Michigan State, Minnesota, Northwestern, Ohio State, Penn State, Purdue and Wisconsin

State of agreement

Article of tropical apparel ... whose start is a state nickname for the state indicated by the circled squares

Unlikely state of a state?

Secretariat's mother, for one ... whose start is a state nickname for the state indicated by the circled squares

State made up of two state postal abbreviations

Emergency worker ... whose start is a state nickname for the state indicated by the circled squares