Nickname for the state of Maryland. According to the Maryland Archives, the origin of the name is as follows:
"The nickname "Free State" was created by Hamilton Owens, editor of the Baltimore Sun. In 1923, Georgia Congressman William D. Upshaw, a firm supporter of Prohibition, denounced Maryland as a traitor to the Union for refusing to pass a State enforcement act. Mr. Owens thereupon wrote a mock-serious editorial entitled "The Maryland Free State," arguing that Maryland should secede from the Union rather than prohibit the sale of liquor. The irony in the editorial was subtle, and Mr. Owens decided not to print it. He popularized the nickname, however, in later editorials."
The current irony is that the state is higly regulated, nearly as much as California; Gun control, drug laws, high taxes, bloated government, etc. Maybe one day it'll live up to its moniker again.