There is no law against scattering ashes on land not designated as state or federal land. However, before scattering ashes on private property, it is advised that the family seek the permission of the property owner.
Many people scatter a loved one's remains in a favorite spot to memorialize them and leave the remains in a place the person enjoyed in life, rather than in a cemetery. This may be a park, on a lake or at sea, depending on where the deceased liked to spend his or her time. If the ashes will be scattered in a town or city's limits, it is always best to consult that city's laws before holding the ceremony. The same holds true for county state laws. Although no one has created laws against it, scattering ashes in the wrong place may pose environmental threats that should be taken into consideration.
Scattering ashes at sea comes with a different set of rules that the family should be aware of. Different areas have different rules but, generally, the ashes should be made to sink to the bottom of the water with little chance they will rise up to the surface. The scattering of ashes at sea should take place at least 3 nautical miles from shore in water that is at last 600 feet deep, with rules differing in other areas.
Pet ashes are prohibited. Time reports that many states turn a "blind-eye" to ocean scatterings within the 3-mile limit but notes that this does not necessarily make it legal. Many national parks, such as the Grand Canyon, allow for scatterings with permission from the chief park ranger.