49 C.F.R. § 71.8 Mountain zone.
Title 49 - Transportation
The fourth zone, the mountain standard time zone, includes that part of the United States that is west of the boundary line between the central and mountain standard time zones described in §71.7 and east of the boundary line between the mountain and Pacific standard time zones described in §71.9.
Title 49: Transportation
PART 71—STANDARD TIME ZONE BOUNDARIES
§ 71.8 Mountain zone.