---
kind: "range"
citation: "15 U.S.C. §§ 261–264"
title: "15"
from: "261"
to: "264"
count: 4
release: "119-102"
url: "https://uscodex.org/usc/15/261..264"
---

# §261. Zones for standard time; interstate or foreign commerce

- (a) **In general—** For the purpose of establishing the standard time of the United States, the territory of the United States shall be divided into nine zones in the manner provided in this section. Except as provided in [section 260a(a) of this title](/usc/15/260a.md?p=a), the standard time of the first zone shall be [Coordinated Universal Time](#b) retarded by 4 hours; that of the second zone retarded by 5 hours; that of the third zone retarded by 6 hours; that of the fourth zone retarded by 7 hours; that of the fifth zone retarded[^1] 8 hours; that of the sixth zone retarded by 9 hours; that of the seventh zone retarded by 10 hours; that of the eighth zone retarded by 11 hours; and that of the ninth zone shall be [Coordinated Universal Time](#b) advanced by 10 hours. The limits of each zone shall be defined by an [order](/usc/15/8702.md?p=14) of the Secretary of Transportation, having regard for the convenience of commerce and the existing junction points and division points of common carriers engaged in interstate or foreign commerce, and any such [order](/usc/15/8702.md?p=14) may be modified from time to time. As used in [sections 261 to 264](/usc/15/261..264.md) of this title, the term “interstate or foreign commerce” means commerce between a [State](/usc/15/267.md), the District of Columbia, the Commonwealth of Puerto Rico, or any possession of the United States and any place outside thereof.
- (b) **Coordinated Universal Time defined—** In this section, the term “Coordinated Universal Time” means the time scale maintained through the General Conference of Weights and Measures and interpreted or modified for the United States by the Secretary of Commerce in coordination with the Secretary of the Navy.

# §262. Duty to observe standard time of zones


Within the respective zones created under the [authority](/usc/15/3051.md?p=1) of [sections 261 to 264](/usc/15/261..264.md) of this title the standard time of the zone shall insofar as practicable (as determined by the Secretary of Transportation) govern the movement of all common carriers engaged in interstate or foreign commerce. In all statutes, [orders](/usc/15/8702.md?p=14), rules, and regulations relating to the time of performance of any act by any officer or department of the United States, whether in the legislative, executive, or judicial branches of the Government, or relating to the time within which any rights shall accrue or determine, or within which any act shall or shall not be performed by any [person](/usc/15/78m.md?p=h-8-E) subject to the jurisdiction of the United States, it shall be understood and intended that the time shall insofar as practicable (as determined by the Secretary of Transportation) be the United States standard time of the zone within which the act is to be performed.


# §263. Designation of zone standard times


The standard time of the first zone shall be known and designated as Atlantic standard time; that of the second zone shall be known and designated as eastern standard time; that of the third zone shall be known and designated as central standard time; that of the fourth zone shall be known and designated as mountain standard time; that of the fifth zone shall be known and designated as Pacific standard time; that of the sixth zone shall be known and designated as Alaska standard time; that of the seventh zone shall be known and designated as Hawaii-Aleutian standard time; that of the eighth zone shall be known and designated as Samoa standard time; and that of the ninth zone shall be known as Chamorro standard time.


# §264. Part of Idaho in fourth zone


In the division of territory, and in the definition of the limits of each zone, as provided in [sections 261 to 264](/usc/15/261..264.md) of this title, so much of the [State](/usc/15/267.md) of Idaho as lies south of the Salmon River, traversing the [State](/usc/15/267.md) from east to west near forty-five degrees thirty minutes latitude shall be embraced in the fourth zone: Provided, That common carriers within such portion of the [State](/usc/15/267.md) of Idaho may conduct their operations on Pacific time.