In the United States, a red state is a state in which a simple majority has voted for the Republican candidate in a presidential election. The term comes from the news networks, which in the 2000 presidential election decided to agree on one color to represent the Republicans and one for the Democrats in the states the parties won.
Voters in red states are considered generally more conservative as a whole than voters in other states. People in red states generally consider themselves committed to conservative Christian morality, pro-life, family values, economic self-sufficiency, and a desire to reduce the tax burden, be sufficiently armed for self-defense, and reduce the degree of government intervention in their lives. This is opposed to, say, the liberal San Francisco values of the blue states. Red states are generally in the southern, western (except the Pacific coast), and midwestern United States. These states are also collectively known as the real America.
One of the main formal platforms of the 2012 Republican party was, and still is, gun rights. This Second Amendment Foundation video shows one of the main differences between liberal gun control Nanny states (Blue states) and conservative and/or libertarian Second Amendment-supporting "free states" (Red states).