Loaded guns will be allowed in Yellowstone, the Grand Canyon and other national parks under a new law that takes effect Monday.
The law lets licensed gun owners bring firearms into national parks and wildlife refuges as long as they are allowed by state law.
The new gun rules come over the objections of gun-control advocates who fear it will lead to increased violence in national parks. They were part of a bill that set new rules for the credit card industry.
A spokesman for the National Park Service says guns will be allowed in all but about 20 of 392 park service locations.
Guns will not be allowed in visitor centers or rangers' offices, because firearms are banned in federal buildings.