Time Has No Boundaries

California Mexico Border

Time Has No Boundaries:
Archaeological Sites Along the U.S.-Mexico Border

Prepared by:

Therese Muranaka
Associate State Archaeologist
and Archaeologist Cynthia Hernandez

Paper Presented at the World Archaeological Congress 5  on Managing Archaeological Resources


Time has no boundaries, no divisions, no fences. It is a continuous flow of people coming and going across empty space. What happens when a political boundary, an international border, is drawn across a prehistoric site? What happens when the site sits under an international boundary fence? Two archaeologists from two different countries of birth, ponder the fate of CA-SDI-222, a 7300 year old site in the far southwestern corner of the continental United States. Threatened by the construction of yet a second fence, and subject to the daily maneuvers of the U.S. Border Patrol, its fate remains to be seen.

IFigure3. Border crossingntroduction

Therese Muranaka, a California State Park archaeologist born and raised in San Diego, works on the San Diego-Tijuana border at Border Field State Park. She has worked at other international crossings before: along the former Russian-Romanian border, along the Arizona-northern Mexico border, and along the California-Baja California line. 

Cynthia Hernández,  is an archaeologist born and raised in Mexico City. She works on the San Diego-Tijuana border at Border Field State Park, and she is a research associate for the University of San Diego’s Anthropology Program. She studied Archaeology at the National School of Anthropology and History (ENAH) and worked at several projects in Teotihuacan.

We two researchers from two different countries walk along this busiest international border in the world (fig. 3).  Billions of dollars of commercial trade change hands here, and millions of people cross (fig. 4) back and forth each year. This is our interpretation of the border, its military presence, and the struggle to discover, interpret, and protect the thousands of years old archaeological sites in the region. Our theme is that borders are accidents of history, not even remotely timeless, and that time has no boundaries, no divisions, and no fences.

Border Field State Park
Border Field State Park
The park we work in, Border Field State Park, is the extreme southwest corner of the continental United States. It is a 418 acre parcel which is part of the 278 unit California State Park system. The park is at the downstream terminus of the 1735 square mile Tijuana River, 73% of which lies on the Mexican side of the border. Border Field State Park is also part of the U.S. federal government’s 2500 acre Tijuana River National Estuarine Research Reserve, and the only coastal lagoon in Southern California which is not bisected by roads and railroads. Habitats include sand dunes and beaches, coastal sage scrub and other communities. The park is home to more than 30 endangered and listed plants and animals, such as the threatened Western Snowy Plover (Charadrius alexandrinus nivosus) and Saltmarsh Bird’s Beak (Cordylanthus maritimus), and the special concern black-tailed jackrabbit (Lepus californicus). This habitat is overseen by a number of federal, state, volunteer, and non-profit agencies such as U.S. National Oceanic and Atmospheric Administration, U.S. Fish and Wildlife, California Fish and Game, California Coastal Commission, California Coastal Conservancy, Southwest Wetlands Interpretive Association, Audubon Society, among others, and is adjacent to lands held publicly by both the City and County of San Diego.

Snowy Plover (Charadrius alexandrinus nivosus) Saltmarsh Bird's Beak (Cordylanthus maritimus) Black-tailed Jackrabbit (Lepus californicus)

Estuary of primarily Pleistocene geologic age

The park is the site of archaeological sites varying in age from 7,300 years ago to yesterday, a full and rich record of the occupation of this estuary of primarily Pleistocene geologic age (left side image). Prehistoric archaeological sites CA-SDI-222 and CA-SDI-4281, in particular, are of note. SDI-222  is C-14 dated at 7260 +/- 80 years B.P. and is up to 1.5 m. in depth.

Eligible for the US National Register of Historic Places, it is aphanitic volcanic lithic scatters now covered with fill for a public park. Labeled "La Jollan" or "Early Archaic", it was recorded in the 1920’s by Malcolm Rogers, San Diego’s most celebrated archaeologist. SDI-4281 is dated at 4340 +/- 50 years. It is less well-understood, and may have dates of greater age due to its close proximity to SDI-222. At this point, it is also hypothesized to be "Archaic" with green Otay Mesa volcanic flakes, unifacially-worked flake tools, handstones (known in Spanish as manos), shell and bone, as well as later Late Prehistoric Age ceramics. Like SDI-222, it is also eligible for the National Register.

SDI-222 is C-14 dated  7260 +/- 80 years B.P. and is up to 1.5 m.  in depth

California Mexico Boundary Marker

Regarding historic sites, the park is also the site of the October, 1849, joint U.S.- Mexico International Boundary Commission which surveyed the newly-created border from California’s Pacific Ocean to Brownsville, Texas, as per agreement in the 1848 Treaty of Guadalupe-Hidalgo, the treaty which ended the U.S.- Mexico War. At the beginning of the Mexican Revolution in 1910, U.S. President Taft ordered 20,000 troops to patrol this U.S. Border. In the early 20th Century, Little Landers, a sectarian colony settled the border.  From 1916 to 1931, Camp Hearn, established for potential skirmishes with the troops of Pancho Villa, was a military presence. From 1940 until 1961, military airstrips, lookout bunkers, hospitals, aerial targets, etc. were located in the park.

Archaeologists today often see even more recent archaeological sites such as plastic combs or cigarettes "drops" where U.S. Border Patrol agents have stopped and searched people crossing the border illegally, making them drop combs (weapons) and cigarette packages (hiding places for needles or drugs), and other personal objects. Some of the canyons and crossings are filled with holy cards, or religious medallions, which name cathedrals or specially-honored saints from specific regions of Mexico and Central America, and which provide much demographic information as to the homelands of these modern migrant peoples.

Border line into ocean

U.S. Immigration and Naturalization Service and Border Patrol Impacts

What happens daily is the Border Patrol drives over these historic and archaeological sites in quick pursuit of people crossing the border between broken fence posts, over fence wires, or around the fence where it hits the water. Known also to come through underground water pipes, or through dug tunnels, people desperate to cross into the United States will try anything to make the crossing. Dangerous coyotes, or traffickers, will charge large amounts of money to "guide" the unsuspecting across in a zone of violence not unlike a military war zone. People die of dehydration, hypothermia and drowning; people are shot by border bandits, as well as Border Patrol agents, and small children have been lost in the crossing.

Archaeologically, since the Border Patrol is allowed to impact up to 60 feet north of the fence during their maneuvers in this zone, military contractors in their urgency will bulldoze archaeological sites or habitat areas without notifying park service. SDI-4281, in particular, is being decimated by "wheelies", or sharp turns in the soil during day and night pursuits in the dry, gray dust. Artifacts lie broken in the trails, and carbon-filled hearths lay exposed to the elements as the vegetation is denuded, and the ocean wind blows the soil cover away.

Border line with church view

A second (and third) border fence for Homeland Security is planned for 250 feet further north of the current, or primary, fence. Efforts to protect the sites are supported by Departments of Fish and Game, Fish and Wildlife, SWIA, Audubon Society and the Sierra Club, among others. There are many places along the U.S.-Mexico border where the secondary fence has been eliminated. Strengthening the primary fence, dropping a second fence below the archaeological sites, building a retractable fence, are options to be considered. The U.S. Army Corps of Engineers, whose plans to test and cap these sites, and place the second barricade on top of them, fails to consider the long-range results of their actions. These results include: the loss of the site to the scientific community, the weight of the capping soil on these irreplaceable sites, as well as impacts to endangered animals and plants. In addition, changes to upstream meanders from landfills to support the new fence would threaten the fragile mesas on which these last sites in the river valley are located, their counterparts on the Tijuana side being long-ago destroyed.

Coastal area


Mexican archaeology faces many of the same problems as other countries: lack of financial support and lack of interest in sites that are not monumental and do not offer any tourist appeal. Accelerating urbanization contributes to the destruction of archaeological sites, that without any protection, will disappear without being satisfactorily studied.  Studying archaeology in Mexico at the National School of Anthropology and History gave the chance to know and recognize the problems that the salvaging of archaeological sites presents. Mexico has laws for the protection of cultural patrimony which are enforced by the National Institute of Anthropology and History; these laws favor archaeological, artistic, and historic monuments (section XXV, article 73, Political Constitution of Mexico).

This order provided for the 1972 Federal Law of Monuments and Archaeological Zones. Though the law provides for the protection of sites whose conservation is in the national interest and of scientific relevance, unfortunately, enforcement of the law is left to the mercy of the Mexican Federal States and is sometimes neglected, as they apply the law according to their particular situation, and the cultural patrimony is left vulnerable to factors such as development, lack of funds for research and preservation, and land use policy decisions, among others that contribute to the deterioration, alteration, and destruction of cultural legacies, despite the efforts of government and private institutions, and local groups.

Eroison evidence

Because of the abundance of archaeological sites in Mexico, it is impossible to protect and conserve every archaeological site. This was the case of the shell midden (left side image)  that we assume existed across the border on the Mexican side in Playas de Tijuana.  Besides the construction of the border that divided Mexico and the United States, on February 10, 1960, Mayor López Hurtado began the construction of the Plaza de Toros del Mar bullfighting ring, in what is now known as Playas de Tijuana (below). There was no archaeological survey before construction of the bull ring, possibly because the presence of hunter-gatherer sites in the zone was unknown.

Plaza de Toros del Mar bullfighting ring in Playas de Tijuana

Miigration tracks

It was not until 1991 that the National Institute of Anthropology and History initiated the Survey to Locate Archaeological Coastal Sites in the Area from Punta Banda to Playas de Tijuana to locate shell middens. More than 200 sites were encountered along the coast, but reaching Playas de Tijuana, the sites that are known on the US side as SDI-222 and SDI-4281 no longer existed on the Mexican side (Jesus Mora, Dirección de Estudios Arqueológicos del INAH, 2003 personal communication).

The land use on both sides of the border is notably different. The Mexican side has businesses, roads, houses, and a bullring only 30 meters from the border, presumably on top of an archaeological site that lacked protection. On the U.S. side, Border Field State Park had been developed by earlier park management, including parking lots, roads, and off-road traffic (pictured). Damage has already been done and continues today with the threat of the construction of a new border fence that will finish off the little that remains of an archaeological site in a conflict zone that thanks to negligence, and the territorial and economic interests of both countries, has been converted into a no-man's land.

To the archaeologist, the military rationale is always in question. Perhaps the INS and U.S. Border Patrol do not know the value of the 7300 year old site? Perhaps their lack of cultural sensitivity may be a defensive posture because of the danger; two agents have lost their lives in our park in recent years. They are concerned that someone will come into the U.S. and destroy " civilization" as it exists. We archaeologists are concerned that they will destroy the record of all "civilizations" so that there is no hope of an understanding its nature at all. We work at cross-purposes. Is there room for a dialogue? Will World War II Italy's Monte Cassino happen over and over again? Will looters like those in modern Baghdad, Iraq, have opportunity again and again? Or will finds like the Ice Man be shared between countries equally appreciative of his value, as was the case between Italy and Austria?

Boundary opening

Those of us who are cultural stewards in military zones and borders have different lives from other archaeological colleagues. We are concerned daily with personal safety, with the need for extreme diplomacy, and the need for speed and accuracy in the assessment and testing of archaeological sites in urgent circumstances. There is the need for an immediate and deep familiarity with federal, state and international antiquity laws. We must understand all types of military equipment and their capability for short and long-range physical damage to the sites we oversee. Sometimes, we benefit from early access to this military technology, for in the use of aerial and satellite photographs, GIS applications, ground-penetrating radar, or electromagnetic resistivity studies, which are now so much a part of our work. We must also, however, be aware of the hazardous materials contamination of the archaeological sites we work in, and the collections we catalogue and curate. On a more personal level, regardless of our politics or personal support for military troops, perhaps even related to us, we are often accused of being "unpatriotic" or "unrealistic" in our pursuit of archaeological site protection which others see, simplistically, as being in opposition to all aspects of "homeland security."


Time protects no one…it goes on unimpeded. It has no boundaries, no divisions, no fences. Historic borders, carefully drawn and maintained, disappear with the drawing of new ones. If there is anything an archaeologist can offer the world, it is the knowledge that civilizations rise and civilizations fall, that things (monuments, ruins, etc.) left behind belong to no country for long. Beyond these current boundaries is where archaeology needs to go. Our job is to globally survey, globally record, and globally unite to protect the heritage of literally millions of years of human evolution.

For those of us very dedicated, an ethnoarchaeological study of warfare is here in our hands. Has warfare, as precisely defined, always existed? What are the processes, as an archaeologist would see them (the taking of sides, the amassing of troops, technological choices, the treatment of the dead, etc.)? Have we recorded these processes for posterity? Are there modern comparisons for those of us who interpret the "warfare" of hundreds, or even thousands of years ago? The famous San Diego scientist, Jonas Salk, who created the polio vaccine to save thousands and thousands of lives, once criticized social scientists, archaeologists among them, that if humans could invent life-saving vaccines in the biological fields, why couldn’t we invent life-saving techniques in the social sciences? Why were we doomed to perpetuate ethnic strife, have and have-not countries, and peoples denied access to basic life-saving goods and services? We military-based archaeologists are being handed the opportunity to study this most terrible of human legacies, warfare, and to remind our own societies that time has no boundaries, no divisions, and no fences.


Bingham, Jeffrey C. 1978 "Archaeological test excavations within Border Field State Park, San Diego County". California Archeological Reports No.16; Cultural Heritage Section; California Department of Parks and Recreation.

McCreary, Scott T. et. al. 2000 Comprehensive Management Plan for Tijuana River National Estuarine Research Reserve and Tijuana Slough National Wildlife Refuge. CONCUR Inc.

Mora-Echeverría, Jesús 1997 "Localización de campamentos arqueológicos costeros en el estado de Baja California, Sector Punta Banda-Playas de Tijuana". En García Cook, Angel et. al (Coord). Homenaje Al Profesor César A. Sáenz. Colección Científica 351. INAH, México.

Sowell, Sarah N. Ed. 2000 The U.S.-Mexico Border XXI Program: Progress Report 1996-2000. US Environmental Protection Agency, Mexican Secretariat of Environment, Natural Resources, and Fisheries.

Schwaderer, Rae 1986 Archaeological test excavations at CA-SDI-4281, Border Field State Park, San Diego County. Cultural Heritage Section; California Department of Parks and Recreation.