Yes, many do. In particular, the far off and exotic peoples of New England permit it, as do the Carolina Tribes and the greater Atlantic Coast Culture of the Murican (muh-REE-ken) People.

(I admit being personally surprised by this. The map is the legal status of cousin marriages in the U.S. Blue it is permitted; powder blue is permitted with some restrictions; pinkish is banned for non-resident marriages; candy apple red is banned; blood red is a criminal penalty. Source: Wikipedia . )