List of principal and guide meridians and base lines of the United States

"Guide Meridian" redirects here. For the highway, see Washington State Route 539.

The following are the principal and guide meridians and base lines of the United States, with the year established and a brief summary of what areas' land surveys are based on each.

Figure 1. This BLM map depicts the principal meridians and baselines used for surveying states (colored) in the PLSS.

List of meridians

Primarily from the United States Government Printing Office Style Manual.^[1] State names usually signify only parts of each listed state, unless otherwise indicated.

Based on the BLM manual's 1973 publication date, and the reference to Clarke's Spheroid of 1866 in section 2-82, coordinates appear to be in the NAD27 datum.

Principal Meridians

Meridian	Longitude	Associated Baseline	Latitude	Adopted	Area surveyed
First principal	84°48′11″W		40°59′22″N	1819[2]	Ohio (NW)
					Indiana (sliver of SE)
Second principal	86°27′21″W		38°28′14″N	1805[2]	Illinois (far E)
					Indiana (almost all)
Third principal	89°08′54″W	Centralia	38°28′27″N	1805[2]	Illinois (most)
Fourth principal	90°27′11″W	Beardstown	40°00′50″N	1815[2]	Illinois (W of Illinois River and 3rd principal meridian)
Fourth principal (extended)	90°25′37″W	Illinois–Wisconsin border	42°30′27″N	1831[2]	Minnesota (NE)
					Wisconsin (all)
Fifth principal	91°03′07″W		34°38′45″N	1815[3]	Arkansas (all)
					Iowa (all)
					Minnesota (most)
					Missouri (all)
					North Dakota (all)
					South Dakota (E half)
Sixth principal	97°22′08″W		40°00′07″N	1855[4]	Colorado (most)
					Kansas (all)
					Nebraska (all)
					South Dakota (some of S)
					Wyoming (most)
Black Hills	104°03′16″W	Black Hills	43°59′44″N	1878[3]	South Dakota (W)
Boise[1]	116°23′35″W		43°22′21″N	1867[5]	Idaho (all)
Chickasaw	89°14′47″W		35°01′58″N	1833[6]	Mississippi
Choctaw	90°14′41″W	Choctaw	31°52′32″N	1821[6]	Mississippi
Cimarron	103°00′07″W		36°30′05″N	1881[7]	Oklahoma (panhandle)
Copper River	145°18′37″W		61°49′04″N	1905[8]	Alaska
Fairbanks	147°38′25.949″W		64°51′50.048″N	1910[8]	Alaska
Gila and Salt River	112°18′19″W		33°22′38″N	1865[9]	Arizona (most)
Humboldt	124°07′10″W		40°25′02″N	1853[10]	California
Huntsville	86°34′16″W		34°59′27″N	1807[6]	Alabama
					Mississippi
Indian	97°14′49″W		34°29′32″N	1870	Oklahoma (most)[7]
Kateel River	158°45′31.014″W		65°26′16.374″N	1956	Alaska[8]
Louisiana	92°24′55″W		31°00′31″N	1807[6]	Louisiana
Michigan	84°21′53″W		42°25′28″N	1815[2]	Michigan
					Ohio
Montana	111°39′33″W		45°47′13″N	1867[11]	Montana
Mount Diablo	121°54′47″W		37°52′54″N	1851[10]	California
					Nevada
Navajo	108°31′59″W	Navajo	35°44′56″N	1869[1][9][12]	Arizona (NE)
					New Mexico (NW, formerly)
New Mexico principal	106°53′12″W		34°15′35″N	1855[13]	New Mexico
					Colorado (SW)
St. Helena	91°09′36″W		30°59′56″N	1819[6]	Louisiana
St. Stephens	88°01′20″W	St. Stephens	30°59′51″N	1805[6]	Alabama
					Mississippi
Salt Lake	111°53′27″W		40°46′11″N	1855[14]	Utah (most)
San Bernardino[10]	116°55′48″W		34°07′13″N	1852[1][5]	California
					Arizona (some townships)
Seward	149°21′26″W		60°07′37″N	1911[8]	Alaska
Tallahassee	84°16′38″W		30°26′03″N	1824[6]	Florida
					Alabama
Uintah	109°56′06″W		40°25′59″N	1875[14]	Utah (part of NE)
Umiat	152°00′04.551″W		69°23′29.654″N	1956[8]	Alaska
Ute	108°31′59″W		39°06′23″N	1880[4]	Colorado
Washington (Mississippi)	91°09′36″W		30°59′56″N	1803[6]	Mississippi
Willamette	122°44′34″W	Willamette	45°31′11″N	1851[15]	Oregon
					Washington
Wind River	108°48′49″W		43°00′41″N	1875[4]	Wyoming (part of W)

Guide Meridians

Meridian	Longitude	Associated Baseline	Latitude	Adopted	Area surveyed	Notes
Ashley guide meridian					Utah[1]
Beaverhead guide meridian					Montana[1]
Belt Mountain guide meridian					Montana[1]
Big Hole guide meridian					Montana[1]
Bitterroot guide meridian					Montana[1]
Boulder guide meridian					Montana[1]
Browning guide meridian					Montana[1]
Buffalo Creek guide meridian					Montana[1]
Carson River guide meridian					Nevada[1]
Castle Valley guide meridian					Utah[1]
Colorado guide meridian					Utah[1]
Columbia guide meridian					Washington[1]
Colville guide meridian					Washington[1]
Coulson guide meridian					Montana[1]
Deer Lodge guide meridian					Montana[1]
Deschutes meridian					Oregon[1]
Emery Valley guide meridian					Utah[1]
Flathead guide meridian					Montana[1]
Fort Belknap guide meridian					Montana[1]
Fremont Valley guide meridian					Utah[1]
Grand River guide meridian					Utah[1]
Grande Ronde guide meridian					Oregon[1]
Green River guide meridian					Utah[1]
Haystack Butte guide meridian					Montana[1]
Helena guide meridian					Montana[1]
Henry Mountain guide meridian					Utah[1]
Horse Plains guide meridian					Montana[1]
Humboldt River guide meridian					Nevada[1]
Jefferson guide meridian					Montana[1]
Judith guide meridian					Montana[1]
Kanab guide meridian					Utah[1]
Kolob guide meridian					Utah[1]
Little Porcupine guide meridian					Montana[1]
Maginnis guide meridian					Montana[1]
Musselshell guide meridian					Montana[1]
New Mexico guide meridian					New Mexico and Colorado[1]
Panguitch guide meridian					Utah[1]
Passamari guide meridian					Montana[1]
Pine Valley guide meridian					Utah[1]
Red Rock guide meridian					Montana[1]
Reese River guide meridian					Nevada[1]
Ruby Valley guide meridian					Nevada[1]
Sevier Lake guide meridian					Utah[1]
Shields River guide meridian					Montana[1]
Smith River guide meridian					Montana[1]
Snake Valley guide meridian					Utah[1]
Square Butte guide meridian					Montana[1]
Sweet Grass guide meridian					Montana[1]
Teton guide meridian					Montana[1]
Valley Creek guide meridian					Montana[1]
Wah Wah guide meridian					Utah[1]
Whatcom County guide meridian	122°30'	Willamette Meridian			Whatcom County, Washington	12 miles east of Willamette Meridian, much of which is in Salish Sea at this latitude.[16] Followed by Guide Road / Old Guide Road / Washington State Route 539 in Whatcom County, Meridian Street in Bellingham, Washington.
Willow Springs guide meridian					Utah[1]
Yantic guide meridian					Montana[1]
Yellowstone guide meridian					Montana[1]

Ohio Lands

Some parts of the Ohio Lands (now Ohio) were laid out in survey townships, but based on other points not listed above:

• Base Line of the United States Military Survey (1797)^[5]
• Great Miami River baseline (1798)^[5]
• Ohio River (1785)^[5] — also part of Indiana^[5]
• Muskingum River baseline (1800)^[5]
• Scioto River baseline (1799)^[5]
• Twelve Mile Square Reserve (1805)^[5]

See also

• Public Land Survey System — the basis of most meridians in the United States