The narrow neck of land, mentioned repeatedly in the Nephite record (Alma 22:32; Alma 50:34; 52:9; Hel. 4:7; Morm.3:5; Ether 10:20), is the key to Book of Mormon geography. Most researchers consider it to be an isthmus which connects the land southward and the land northward. If this geographic feature could be positively identified it would solve the riddle of Book of Mormon lands, and all else would fall naturally into place. Many different possibilities have been suggested, from the Isthmus of Panama to a strip of land between two of the Great Lakes. However, in my opinion all of the suggested sites fail to meet the criteria set forth in the Book of Mormon.


 Most modern researchers are of the opinion that the Isthmus of Tehuantepec, in southern Mexico, is this northward trending narrow neck of land. However this site also seems to fall short of the mark being neither narrow or northerly.  Naturally I have my own opinion which I will present shortly. But before we talk about specifics, consider the criteria for this landmark which are outlined in the Book of Mormon.


    It should be oriented in a general north-south direction (Alma 22:32).


    It is flanked by a west sea and an east sea (Alma 22:32).


    It should be located at a place where "the sea divides the land" (Ether 10:20).


    It should have a separate feature called the "narrow pass" which is narrower than the neck itself (Alma 50:34; 52:9).


    It could be traversed in 1 to 1 1/2 days (this would make it approximately 15-40 miles wide.  See discussion on distances.) (Alma 22:32; Hel.4:7).


    It was at a lower elevation than the higher land to the south (Morm.4:1,19).


    The combined land of Zarahemla and Nephi, southward from the Narrow Neck, was almost completely surrounded by water.  It was small enough that the inhabitants considered their land an island (Alma 22:32; 2Ne.10:20- 21).


    At one time in Jaredite history the narrow neck was blocked by an infestation of poisonous snakes to such and extent that neither man nor beast could pass.  This barrier lasted for eight generations of Jaredite kings (300-400 years). (This would normally only occur if there were a water barrier on both sides, and in a warm climate where snakes would not hibernate during a cold season.) (Ether 9:31-34).


    It formed the border between the Land of Bountiful and the Land of Desolation (Alma 22:31-32).


    The city of Desolation was located toward the southern portion of the narrow neck, and probably near the east sea (Morm.3:5-7).


    Lib, a Jaredite king, built a "great city" at the narrow neck (this may have been in the same area as the city of Desolation) (Ether 10:20).


    The city of Bountiful was some distance south and eastward from the narrow neck-- probably at least a days journey (Alma 50:32-34).


    It should be an area which would be easy to fortify (Alma 52:9; Morm.3:5-6).


    The Jaredites did not inhabit the land south of the narrow neck, but reserved it as a wilderness for hunting, at least following the time of Lib (about 900 BC), and there is no record of any Jaredite cities located there during the early Jaredite years. Therefore there should be no remnants of ancient Jaredite cities south of the narrow neck (Ether 10:21).  If the Olmec are equivalent to the Jaredites, which I believe is correct, this would mean that there should be no evidence of Olmec cities south of the narrow neck of land.


    During the Nephite era the land northward from the narrow neck was essentially treeless (Hel.3:5-10).


    The Nephites were probably not aware of the narrow neck until sometime after 150 B.C. (following Mosiah's arrival in Zarahemla). The first mention of the land northward is about 121 B.C. when it was explored by Limhi's search party (Mosiah 8:8).  The next reference is about 90 B.C. and this was a commentary by the abridger Mormon writing about 340 AD (Alma 22:31-2).


Now that we have the criteria in place, let us proceed with my proposal.




I suggest that the Isthmus of Rivas on the Pacific side of Nicaragua is the narrow neck of land referred to in the Book of Mormon. This may seem odd to most students of Book of Mormon geography as this minor isthmus does not appear to be a significant feature that would isolate Nicaragua from Costa Rica. But in fact it is.  So be patient and I will try and illustrate the logic of this proposal.


The Isthmus of Rivas is a low lying strip of land between the Pacific Ocean on the west, and Lake Nicaragua on the east. On the western side the isthmus is composed of a low range of coastal mountains parallelling the Pacific coast. These hills reach a maximum height of 1800 feet. A lowlying plain, about 4-10 miles wide, and averaging 100 feet above sea level, forms a corridor bordering Lake Nicaragua. This plain is gradually narrowed by the encroaching western mountains until at the southern end it forms a narrow valley which is only several miles wide. At the narrowest point on the isthmus, south of the city of Rivas, it is about 15 miles wide. Its north-south length is approximately 100 miles. This area of Nicaragua has a wet season from May to December, and a dry season from January through April. It averages 35 inches annual precipitation, and average temperatures range from 20 degrees Celsius (68 degrees Fahrenheit) to 44 degrees Celsius (93 degrees Fahrenheit).


The vegetation consists of pasture and open grassland on the plain, with an occasional Guanacaste tree, and grass interspersed with sparse trees and brush in the hills and mountains.  The area is mainly used for livestock grazing at the present time.  Prior to modern cultivation the area would have been classed as tropical savannah.  There is no jungle or densely vegetated forestland, at least from Rivas almost to the Costa Rican border.


Due to the topography of Nicaragua and Costa Rica, the Isthmus of Rivas has been the natural and exclusive route of travel since pre-conquest times. It presents few barriers, and provides many amenities to the traveler. All land traffic, whether north or south is naturally funneled through this isthmus. It was the  only terrestrial pre-Columbian trade route, was the route of the Spanish conquistadors, and continues to be the exclusive modern route with the Panamerican Highway following its gentle course.  It was  also likely the exclusive route of ancient peoples during Book of Mormon times.


In close association with the Isthmus of Rivas is the adjacent Lake Nicaragua. This lake is the largest freshwater body of water in Central America, and the dominant physical feature of Nicaragua. The Indian name for the lake was Cocibolca, meaning "sweet sea".  The Spanish called it Mar Dulce. It is oval in shape, has a surface area of 3,149 square miles, is 110 miles in length, and has an average width of 36 miles.  It is about 60 feet deep in the center, but reaches a maximum depth of 200 feet (105 feet deeper than sea level) southeast of the island of Ometepe. Its surface is 95 feet above sea level. More than 40 rivers drain into the lake (mainly from the eastern mountains).


The San Juan River, which drains the lake and connects it with the Caribbean to the east, is 112 miles long and averages 1000 feet in width. This river is an effective barrier which separates the land masses of Costa Rica and Nicaragua. On its eastward course to the sea, it passes through a densely forested region which is the least inhabited area of either country. This lack of habitation is due to the inhospitable nature of the country and climate (dense jungle, high rainfall, high humidity and high temperatures), and to the difficulty in building and maintaining roads. Even in our day no bridges span the river, no ferries cross it, and no interconnecting roads end at its banks. At the outlet from Lake Nicaragua, and more so in the eastern delta region, there are vast areas of swamp and wetlands blocking any attempt at foot travel. Historically, the river has been a route for shallow-draft boat traffic, and was once even considered the favored route for the interoceanic canal until that route was replaced by the Panamanian one.  As there has been heavy alluviation from the adjacent Costa Rican volcanoes in the last several millenia (up to a possible ten feet of volcanic ash), it is entirely possible that in Book of Mormon times the San Juan River Basin was lower in elevation thus increasing its size as a water barrier, and possibly even featured an ocean embayment.  However, this proposal is valid even with the present topography. Increasing the size of the river, and submerging the present wetlands under the Caribbean, would only enhance its potential as a barrier.


How does the Isthmus of Rivas match the criteria outlined above for the Narrow Neck of land? It is oriented in a northwest-southeast direction, bordered on the west by the Pacific (west sea), and on the east by Lake Nicaragua (east sea). Lake Nicaragua divides Pacific Nicaragua from the eastern highlands, hence "the place where the sea divides the land" (Ether 10:20.) The narrow plains near Penas Blancas at the Nicaraguan/Costa Rican border, where the coastal mountains wedge in almost to the lake, could be the feature called the "narrow pass". The isthmus is narrow enough to be easily cross by foot in a day  (See discussion on distances.)


The isthmus is much lower than the Guanacaste highlands, to the immediate south in Costa Rica, which reach heights above 6000 feet. The land mass of Costa Rica/Panama could easily be considered an "isle" and is at least 80-90% surrounded by the Pacific and Caribbean. This is something that the average Nephite would have been visually aware of. By climbing one of the taller mountains in Costa Rica, one can see the oceans on both sides, and possibly Lake Nicaragua and the isthmus as well. In conjunction with the lake and the San Juan River, the isthmus forms a natural boundary between the lands to the north and south.


There were substantial native populations at the time of the Spanish conquest. Oviedo(1) estimated that there were 600,000 people living in Nicaragua when the Spaniards arrived. Martyr records that there were 6 large towns with 2000 houses each. Squires(2) observes that Leon, Nicaragua, at the north end of the isthmus, was built on, and adjacent to the original Indian town of Subtiaba, and Granada was established next to the native town of Jalteba. Although no ruins similar to those in Mexico or Guatemala have been found in Nicaragua, there are many large stone carvings similar to the Mesoamerican ones. These have mainly been found on the islands in Lake Nicaragua where they had been taken and buried by the natives to hide them from the Spanish priests who were zealously destorying them. There are many ancient sites with evidence of habitation. Some of these have been excavated and studied. However, south of the Isthmus of Rivas, there are none of the large stone Maya, Aztec or Olmec ruins of Jaredite design.


The isthmus is a strategically significant area, and could easily be fortified by a large military group, concentrating the majority of its forces on the level plain next to the lake. It is difficult to assess the lack of trees during the Nephite era; however, the isthmus is characterized by open savannah and somewhat sparser tree cover than is common for the area. But something such as tree cover can vary greatly over a thousand years. The Jaredite plague of poisonous snakes is also difficult to assess. This area would certainly be amenable to such an occurance. Once the isthmus were blocked in this or any other way, north-south human and animal traffic would be stopped. This would not be so in the case of a land bound barrier. Neither mountains, wilderness, swamps, or jungle, no matter how rugged or impenetrable, can prevent wild animals from passing through. And a persistent man can penetrate the worst jungles, and pass through the most rugged mountains, if given the time and the motivation. But wide bodies of water prove to be effective barriers for man or animal, and will impede man unless he uses watercraft. Lake Nicaragua, the Pacific Ocean and the San Juan River basin combine to create such a barrier. It should also be noted that there is currently a healthy population of snakes in the Guanacaste area of Costa Rica, south of the Rivas isthmus.


The Rivas region appears to have been a natural dividing line between northern and southern cultures.  Solc (3) observes that "The territory of Nicaragua and Costa Rica is undeniably the meeting-place of the Central and South American cultures [Jaredite and Nephite?]. The Maya and Mexican influence is evident as far [south] as the Nicoya peninsula [in northwestern Costa Rica.]”


Considering all these factors, it appears that there is a strong correlation between the Isthmus of Rivas in Nicaragua and the narrow neck of land described in the Book of Mormon.  In fact I will be so bold as to say that it is the only isthmus in the entire western hemisphere which meets all the criteria.






(1)  Oviedo y Valdes, Gonzalo Fernandez de. Historia General de las Indias, Islas y Tierra Firme del Mar Oceano (1945; first 19 books originally published in 1535).


(2)  Squires, E.G. Nicaragua; its People, Scenery, Monuments, Resources, Condition, and Proposed Canal. Harper and Brothers, Publishers. New York. 1860.


(3)  Solc, Vaclav.  Chiriqui Culture.  Naprstek Museum.  Prague.  1970.  p.12.