The Native American reservations in the United States are considered sovereign land which means the Supreme Court law allowing same sex marriages does not need to be followed there.

The Navajo and Cherokee are the largest Native American tribes (with 600,000 members collectively) and have both reaffirmed their decades old tribal laws banning gay marriage...

...Mr. Co-Cke says Christianity's influence on the tribes ever since the reservations were formed has influenced their stances on homosexuality.