US lawFederal (United States)RegulationsTitle 40 CFR — Protection of EnvironmentChapter I — ENVIRONMENTAL PROTECTION AGENCYPart 81 — DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSESSubpart D — Identification of Mandatory Class I Federal Areas Where Visibility Is an Important Value81.42340 C.F.R. § 81.423North Dakota.Last amended: 2016Year: 2026Length: 26 wordsOfficial source Cite as 40 C.F.R. § 81.423 (2026)Area name Acreage Public Law establishing Federal land manager Lostwood Wild 5,557 93-632 USDI-FWS. Theodore Roosevelt, NP 69,675 80-38 USDI-NPS. [54 FR 41098, Oct. 5, 1989]Previous40 C.F.R. § 81.422Next40 C.F.R. § 81.424