The Uniform Time Act of 1966 (1983 / 1986 / 2000 Updates)
The first law on this page transferred functions to the Secretary of Transportation. The transfer from the Interstate Commerce Commission occurred in 1966 but the US Code had not been updated.

The second law on this page renamed the sixth, seventh and eighth zones.

The two 1983 changes are combined in this section. July 1986 and December 2000 changes are below.
PL 97-449
AN ACT
To revise, codify, and enact without substantive change certain general and permanent laws related to transportation as subtitle I and chapter 31 of subtitle II of title 49, United States Code, "Transportation".

Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled,
. . .
SEC 2. (c) The Act of March 19, 1918 (15 U.S.C. 261-264), the Act of March 4,1921 (15 U.S.C. 265), and the Uniform Time Act of 1966 (15 U.S.C. 260, 260a, 261-263, 266, 267) are amended by striking out the words "Interstate Commerce Commission" wherever they appear and substituting "Secretary of Transportation".
. . .
Approved January 12, 1983.

PL 98-181
AN ACT
Making supplemental appropriations for the fiscal year ending September 30, 1984, and for other purposes.

Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled,
. . .
TITLE II
GENERAL PROVISIONS
. . .
SEC. 2003.
  1. Section 4 of the Act entitled "An Act to save daylight and to provide standard time for the United States", approved March 19,1918 (15 U.S.C. 263), is amended—
    (1) by striking out "Yukon" and inserting in lieu thereof "Alaska";
    (2) by striking out "Alaska-Hawaii" and inserting in lieu thereof "Hawaii-Aleutian"; and
    (3) by striking out "Bering" and inserting in lieu thereof "Samoa".
  2. (1) Any reference to Yukon standard time in any law, regulation, map, document, record, or other paper of the United States shall be held and considered to be a reference to Alaska standard time.
    (2) Any reference to Alaska-Hawaii standard time in any law, regulation, map, document, record, or other paper of the United States shall be held and considered to be a reference to Hawaii-Aleutian standard time.
    (3) Any reference to Bering standard time in any law, regulation, map, document, record, or other paper of the United States shall be held and considered to be a reference to Samoa standard time.
. . .
Approved January 12, 1983.
First
Zone		 Second
Zone		 Third
Zone		 Fourth
Zone		 Fifth
Zone		 Sixth
Zone		 Seventh
Zone		 Eighth
Zone
60° W 75° W 90° W 105° W 120° W 135° W 150° W 165° W
UTC-04 UTC-05 UTC-06 UTC-07 UTC-08 UTC-09 UTC-10 UTC-11
Atlantic
standard
time		 eastern
standard
time		 central
standard
time		 mountain
standard
time		 Pacific
standard
time		 Yukon
Alaska
standard
time		 Alaska-Hawaii
Hawaii-Aleutian
standard
time		 Bering
Samoa
standard
time

15 U.S.C.

§260.
It is the policy of the United States to promote the adoption and observance of uniform time within the standard time zones prescribed by the Act entitled "An Act to save daylight and to provide standard time for the United States", approved March 19, 1918 (40 Stat. 450; 15 U.S.C. 261-264), as modified by the Act entitled "An Act to transfer the Panhandle and Plains section of Texas and Oklahoma to the United States standard central time zone", approved March 4,1921 (41 Stat. 1446; 15 U.S.C. 265). To this end the Interstate Commerce Commission Secretary of Transportation is authorized and directed to foster and promote widespread and uniform adoption and observance of the same standard of time within and throughout each such standard time zone.
(Pub. L. 89–387, §2, Apr. 13, 1966, 80 Stat. 107; Pub. L. 97–449, §2(c), Jan. 12, 1983, 96 Stat. 2439.)

(a) During the period commencing at 2 o'clock antemeridian on the last Sunday of April of each year and ending at 2 o'clock antemeridian on the last Sunday of October of each year, the standard time of each zone established by the Act of March 19, 1918 (15 U.S.C. 261-264), as modified by the Act of March 4, 1921 (15 U.S.C. 265), shall be advanced one hour and such time as so advanced shall for the purposes of such Act of March 19,1918, as so modified, be the standard time of such zone during such period; however, (1) any State that lies entirely within one time zone may by law exempt itself from the provisions of this subsection providing for the advancement of time, but only if that law provides that the entire State (including all political subdivisions thereof) shall observe the standard time otherwise applicable during that period, and (2) any State with parts thereof in more than one time zone may by law exempt either the entire State as provided in (1) or may exempt the entire area of the State lying within any time zone.

(b) It is hereby declared that it is the express intent of Congress by this section to supersede any and all laws of the States or political subdivisions thereof insofar as they may now or hereafter provide for advances in time or changeover dates different from those specified in this section.

(c) For any violation of the provisions of this section the Interstate Commerce Commission Secretary of Transportation or its duly authorized agent may apply to the district court of the United States for the district in wnich such violation occurs for the enforcement of this section; and such court shall have jurisdiction to enforce obedience thereto by writ of injunction or by other process, mandatory or otherwise, restraining against further violations of this section and enjoining obedience thereto.
(Pub. L. 89–387, §3, Apr. 13, 1966, 80 Stat. 107; Pub. L. 92–267, Mar. 30, 1972, 86 Stat. 116; Pub. L. 97–449, §2(c), Jan. 12, 1983, 96 Stat. 2439.)

§261. SEC. 1
That for the purpose of establishing the standard time of the United States, the territory of the United States shall be divided into eight zones in the manner provided in this section. Except as provided in section 3(a) of the Uniform Time Act of 1966, the standard time of the first zone shall be based on the mean solar time of the sixtieth degree of longitude west from Greenwich; that of the second zone on the seventy-fifth degree; that of the third zone on the ninetieth degree; that of the fourth zone on the one hundred and fifth degree; that of the fifth zone on the one hundred and twentieth degree; that of the sixth zone on the one hundred and thirty-fifth degree; that of the seventh zone on the one hundred and fiftieth degree; and that of the eighth zone on the one hundred and sixty-fifth degree. The limits of each zone shall be defined by an order of the Interstate Commerce Commission 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 may be modificd from time to time. As used in this Act, the term 'interstate or foreign commerce' means commerce between a State, the District of Columbia, the Commonwealth of Puerto Rico, or any possession of the United States, and any place outside thereof.
(Mar. 19, 1918, ch. 24, §1, 40 Stat. 450; Pub. L. 89–387, §4(a), Apr. 13, 1966, 80 Stat. 108; Pub. L. 97–449, §2(c), Jan. 12, 1983, 96 Stat. 2439.)

§262. SEC. 2
Within the respective zones created under the authority of this Act the standard time of the zone shall insofar as practicable (as determined by the Interstate Commerce Commission Secretary of Transportation) govern the movement of all common carriers engaged in interstate or foreign commerce. In all statutes, orders, 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 an act shall or shall not be performed by any person 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 Interstate Commerce Commission Secretary of Transportation) be the United States standard time of the zone within which the act is to be performed.
(Mar. 19, 1918, ch. 24, §2, 40 Stat. 451; Pub. L. 89–387, §4(b), Apr. 13, 1966, 80 Stat. 108; Pub. L. 97–449, §2(c), Jan. 12, 1983, 96 Stat. 2439.)

§263. SEC. 4
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 Yukon Alaska standard time; that of the seventh zone shall be known and designated as Alaska-Hawaii Hawaii Aleutian standard time; and that of the eighth zone shall be known and designated as Bering Samoa standard time.
(Mar. 19, 1918, ch. 24, §4, 40 Stat. 451; Pub. L. 89–387, §4(c), Apr. 13, 1966, 80 Stat. 108; Pub. L. 98–181, title II, §2003(a), Nov. 30, 1983, 97 Stat. 1297.)

§264. SEC. 3
In the division of territory, and in the definition of the limits of each zone, as hereinbefore provided, so much of the State of Idaho as lies south of the Salmon River, traversing the State from east to west near forty-five degrees thirty minutes latitude shall be embraced in the third zone: Provided, That common carriers within such portion of the State of Idaho may conduct their operations on Pacific time.
(Mar. 19, 1918, ch. 24, §3, as added Mar. 3, 1923, ch. 216, 42 Stat. 1434; amended June 24, 1948, ch. 631, §1, 62 Stat. 646.)

§265.
That the Panhandle and Plains section of Texas and Oklahoma be, and the same are hereby, transferred to and placed within the United States standard central time zone.
The Interstate Commerce Commission Secretary of Transportation is hereby authorized and directed to issue an order placing the western boundary line of the United States standard central time zone in so far as the same affect Texas and Oklahoma as follows:
Beginning at a point where such western boundary time zone line crosses the State boundary line between Kansas and Oklahoma; thence westerly along said State boundary line to the northwest corner of the State of Oklahoma; thence in a southerly direction along the west State boundary line of Oklahoma and the west State boundary line of Texas to the southeastern corner of the State of New Mexico; thence in a westerly direction along the State boundary line between the States of Texas and New Mexico to the Rio Grande River; thence down the Rio Grande River as the boundary line between the United States and Mexico: Provided, That the Chicago, Rock Island and Gulf Railway Company and the Chicago, Rock Island and Pacific Railway Company may use Tucumcari, New Mexico, as the point at which they change from central to mountain time and vice versa; the Colorado Southern and Fort Worth and Denver City Railway Companies may use Sixela, New Mexico, as such changing point; the Atchison, Topeka and Santa Fe Railway Company and other branches of the Santa Fe System may use Clovis, New Mexico, as such changing point, and those railways running into or through El Paso may use El Paso as such point: Provided further, That this Act shall not, except as herein provided, interfere with the adjustment of time zones as established by the Interstate Commerce Commission Secretary of Transportation.
(Mar. 4, 1921, ch. 173, §1, 41 Stat. 1446; Pub. L. 97–449, §2(c), Jan. 12, 1983, 96 Stat. 2439.)

§266. SEC. 5
The Administrative Procedure Act (5 U.S.C. 1001-1011) shall apply to all proceedings under this Act, the Act of March 19, 1918 (15 U.S.C. 261-264), and the Act of March 4, 1921 (15 U.S.C. 265).
(Pub. L. 89–387, §5, Apr. 13, 1966, 80 Stat. 108.)

§267. SEC. 6.
As used in this Act, the term "State" includes the District of Columbia, the Commonwealth of Puerto Rico, or any possession of the United States.
(Pub. L. 89–387, §7, Apr. 13, 1966, 80 Stat. 109.)
PL 99-359
AN ACT
To authorize appropriations for activities under the Federal Fire Prevention and control Act of 1974.

Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled,
. . .
SEC. 2.
  1. The Congress finds—
    1. that various studies of governmental and nongovernmental agencies indicate that daylight saving time over an expanded period would produce a significant energy savings in electrical power consumption;
    2. that daylight saving time may yield energy savings in other areas besides electrical power consumption;
    3. that daylight saving time over an expanded period could serve as an incentive for further energy conservation by individuals, companies, and the various governmental entities at all levels of government, and that such energy conservation efforts could lead to greatly expanded energy savings; and
    4. that the use of daylight saving time over an expanded period could have other beneficial effects on the public interest, including the reduction of crime, improved traffic safety, more daylight outdoor playtime for the children and youth of our Nation, greater utilization of parks and recreation areas, expanded economic opportunity through extension of daylight hours to peak shopping hours and through extension of domestic office hours to periods of greater overlap with the European Economic Community.
  2. Section 3(a) of the Uniform Time Act of 1966 (15 U.S.C. 260a(a)) is amended by striking "last Sunday of April" and inserting in lieu thereof "first Sunday of April".
  3. Any law in effect on the date of the enactment of this Act—
    1. adopted pursuant to section 3(a)(2) of the Uniform Time Act of 1966 by a State with parts thereof in more than one time zone, or
    2. adopted pursuant to section 3(a)(1) of such Act by a State that lies entirely within one time zone,
    shall be held and considered to remain in effect as the exercise by that State of the exemption permitted by such Act unless that State, by law, provides that such exemption shall not apply.
  4. . . .
  5. This section shall take effect 60 days after the date of enactment of this Act, except that if such effective date occurs in any calendar year after March 1, this section shall take effect on the first day of the following calendar year.

Approved July 8, 1986.
(Effective January 1, 1987)
. . .
§261. SEC. 1
(a) During the period commencing at 2 o'clock antemeridian on the last first Sunday of April of each year and ending at 2 o'clock antemeridian on the last Sunday of October of each year, the standard time of each zone established by the Act of March 19, 1918 (15 U.S.C. 261-264), as modified by the Act of March 4, 1921 (15 U.S.C. 265), shall be advanced one hour and such time as so advanced shall for the purposes of such Act of March 19,1918, as so modified, be the standard time of such zone during such period; however, (1) any State that lies entirely within one time zone may by law exempt itself from the provisions of this subsection providing for the advancement of time, but only if that law provides that the entire State (including all political subdivisions thereof) shall observe the standard time otherwise applicable during that period, and (2) any State with parts thereof in more than one time zone may by law exempt either the entire State as provided in (1) or may exempt the entire area of the State lying within any time zone.

(b) It is hereby declared that it is the express intent of Congress by this section to supersede any and all laws of the States or political subdivisions thereof insofar as they may now or hereafter provide for advances in time or changeover dates different from those specified in this section.

(c) For any violation of the provisions of this section the Secretary of Transportation or its duly authorized agent may apply to the district court of the United States for the district in wnich such violation occurs for the enforcement of this section; and such court shall have jurisdiction to enforce obedience thereto by writ of injunction or by other process, mandatory or otherwise, restraining against further violations of this section and enjoining obedience thereto.
(Pub. L. 89–387, §3, Apr. 13, 1966, 80 Stat. 107; Pub. L. 92–267, Mar. 30, 1972, 86 Stat. 116; Pub. L. 97–449, §2(c), Jan. 12, 1983, 96 Stat. 2439; July 8, 1986, 100 Stat. 764.)
. . .
PL 106-564
AN ACT
To establish a standard time zone for Guam and the Commonwealth of the Northern Mariana Islands,
and for other purposes.

Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled,

SECTION 1. TIME ZONE ESTABLISHED.
  1. IN GENERAL.— The first section of the Act of March 19, 1918 (15 U.S.C. 261; commonly known as the Calder Act) is amended—
    1. in the first sentence, by striking "eight zones" and inserting "nine zones"; and
    2. in the second sentence—
      1. by striking "; and that of the eighth" and inserting "; that of the eighth"; and
      2. by inserting before the period the following: "; and that of the ninth zone on the one hundred and fiftieth meridian of longitude east from Greenwich.".
  2. NAME OF ZONE.—Section 4 of the Act of March 19, 1918 (15 U.S.C. 263; commonly known as the Calder Act) is amended—
    1. by striking "and that of the eighth" and inserting "that of the eighth"; and
    2. by inserting before the period the following: "; and that of the ninth zone shall be known as Chamorro standard time".
  3. DAYLIGHT SAVING TIME.—Section 7 of the Uniform Time Act of 1966 (15 U.S.C. 267) is amended by inserting "Guam, the Commonwealth of the Northern Mariana Islands," after "Puerto Rico,".

Approved December 23, 2000.
First
Zone		 Second
Zone		 Third
Zone		 Fourth
Zone		 Fifth
Zone		 Sixth
Zone		 Seventh
Zone		 Eighth
Zone		 Ninth
Zone
60° W 75° W 90° W 105° W 120° W 135° W 150° W 165° W 150° E
UTC-04 UTC-05 UTC-06 UTC-07 UTC-08 UTC-09 UTC-10 UTC-11 UTC+10
Atlantic
standard
time		 eastern
standard
time		 central
standard
time		 mountain
standard
time		 Pacific
standard
time		 Alaska
standard
time		 Hawaii-Aleutian
standard
time		 Samoa
standard
time		 Chamorro
standard
time

§261. SEC. 1
That for the purpose of establishing the standard time of the United States, the territory of the United States shall be divided into eight zones in the manner provided in this section. Except as provided in section 3(a) of the Uniform Time Act of 1966, the standard time of the first zone shall be based on the mean solar time of the sixtieth degree of longitude west from Greenwich; that of the second zone on the seventy-fifth degree; that of the third zone on the ninetieth degree; that of the fourth zone on the one hundred and fifth degree; that of the fifth zone on the one hundred and twentieth degree; that of the sixth zone on the one hundred and thirty-fifth degree; that of the seventh zone on the one hundred and fiftieth degree; and that of the eighth zone on the one hundred and sixty-fifth degree; and that of the ninth zone on the one hundred and fiftieth meridian of longitude east from Greenwich.. The limits of each zone shall be defined by an order 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 may be modificd from time to time. As used in this Act, the term 'interstate or foreign commerce' means commerce between a State, the District of Columbia, the Commonwealth of Puerto Rico, or any possession of the United States, and any place outside thereof.
(Mar. 19, 1918, ch. 24, §1, 40 Stat. 450; Pub. L. 89–387, §4(a), Apr. 13, 1966, 80 Stat. 108; Pub. L. 97–449, §2(c), Jan. 12, 1983, 96 Stat. 2439; Pub. L. 106–564, §1(c), Dec. 23, 2000, 114 Stat. 2811.)
. . .
§263. SEC. 4
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; and 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.
(Mar. 19, 1918, ch. 24, §4, 40 Stat. 451; Pub. L. 89–387, §4(c), Apr. 13, 1966, 80 Stat. 108; Pub. L. 98–181, title II, §2003(a), Nov. 30, 1983, 97 Stat. 1297; Pub. L. 106–564, §1(c), Dec. 23, 2000, 114 Stat. 2811.)
. . .
§267. SEC. 6.
As used in this Act, the term "State" includes the District of Columbia, the Commonwealth of Puerto Rico, Guam, the Commonwealth of the Northern Mariana Islands, or any possession of the United States.
(Pub. L. 89–387, §7, Apr. 13, 1966, 80 Stat. 109; Pub. L. 106–564, §1(c), Dec. 23, 2000, 114 Stat. 2811.)
1918-1919-1921-1923 1966-1972 1983-1986-2000 2005-2007 PROPOSED