Designated by Congress in the 1977 amendments to the Clean Air Act (CAA § 162(a))
Areas in existence prior to August 1977, including:
International Parks
national memorial parks and national wilderness areas exceeding 5,000 acres
national parks exceeding 6,000 acres
May not be redesignated
Federal
Federal lands within a state or tribal lands, designated by EPA at the request of the state or tribe (Indian lands held in trust not considered federal lands under the PSD program), including:
national monuments, national primitive areas and national preserves, national recreation areas, national wild and scenic rivers, national wildlife refuges, national lakeshores or national seashores exceeding 10,000 acres. CCA 164(a)
national park or national wilderness area established after August 7, 1977, exceeding 10,000 acres
No Federal Class I areas requested presently
Can be redesignated to Class I or Class II only
Non-Federal
Lands under the jurisdiction of a state or a tribe may be redesignated to Class I at the request of that state or that tribe
No size/acreage restrictions
No state Class I redesignations requested presently
Five Tribal Reservations have been redesignated as of 2014
