By James Vicini

WASHINGTON (Reuters) - The Supreme Court refused Monday to consider whether an individual's right to own guns includes carrying a firearm outside the home, staying out of one of the nation's most divisive social, political and legal issues.

The justices let stand a ruling by Maryland's highest court that upheld a state law prohibiting the carrying of a handgun without a permit outside of one's home.

The court turned down the opportunity to define the reach of its landmark 2008 ruling that the constitutional right to keep and bear arms applies to individuals and allows them to use guns for lawful purposes such as self-defense in the home.

The Supreme Court ruled in 2010 that gun rights applied not just to federal laws, but to state and city laws as well. The court's rulings in the gun cases have been closely divided, by 5-4 votes and split along conservative and liberal lines.

Gun rights has long been a contentious issue. The United States has the world's highest civilian gun ownership rate, with some 90 million Americans owning an estimated 200 million guns.

At issue in the new case from Maryland is whether that right extends to carrying a gun outside the home. The Supreme Court without comment rejected an appeal by Charles Williams, who was convicted of unlawful gun possession.

Williams bought his handgun legally from a licensed dealer in August 2007, but never applied for a permit.

A police officer from Prince George's County on October 1, 2007, saw Williams standing behind a bus stop, pulling items out of a book bag near the woods.

When asked what he had hidden in the bushes, Williams replied, "My gun." The officer then retrieved the handgun, a black Glock with 15 rounds in the magazine.

Williams, who had been transporting the gun from his girlfriend's house to his residence, was convicted of violating a state law prohibiting the wearing, carrying or transporting of a firearm in public without a permit.

He was sentenced to three years in prison, with all but one year suspended, and to three years of probation.

Stephen Halbrook, an attorney for Williams, said in the appeal that the Supreme Court so far has only ruled on the right to keep a handgun in the home, but argued the right also existed outside the home.

Maryland Attorney General Douglas Gansler opposed the appeal. He defended the state law and said it protected an individual's right to have a handgun in the home and carry one on the street with a permit.

The Supreme Court case is Charles Williams v. Maryland, No. 10-1207.

(Reporting by James Vicini, Editing by Eric Beech)