What exactly is “the underground?”

When the Missoula Historic Underground Project began we had the same question. We didn’t really know exactly where to go (other than…down?) and what to look for when we got there. After about a year of visiting spaces, which were for the most part under downtown businesses, it was possible to determine that we were working with primarily four units of analysis.

Units of analysis in research are the primary items being studied and they provide the basis for data gathering.[i] The four underground units of analysis that we have dealt with on this project so far are: 1) steam tunnels; 2) non-steam tunnels; 3) basements; and 4) sidewalk voids. Further research could result in the discovery of additional units of analysis.

The term underground has many connotations, the most common being in reference to anything beneath the surface of the ground (subterranean space). Of course, the term also conjures up images of secret activities and delinquent persons committing acts they prefer to be hidden from authorities and the rest of the community. Most often these are of a religious, social, cultural, political or illegal nature, and sometimes more than one of these factors could be involved. The underground spaces in many cities are assumed to be linked to much more nefarious activity than data generally supports. At the same time, the lore exists for a reason. The primary definition we work with is the simplified definition of any “subterranean space.”

Steam tunnels are man-made tunnels that run under the city streets with the intended purpose of providing steam to downtown buildings for heat. For this project, steam tunnels are those that either still include steam pipes, designating their intended purpose, and/or those indicated on the city steam tunnel map.


Steam tunnel access. Photo: Jared Fischer, 2012.

Although there are rumors of a network of tunnels beneath the city streets, other than steam tunnels, only two other tunnels have been discovered. These are referred to as the non-steam tunnels. There is a lengthy tunnel that extends from the basement of a historic building that was explored but has not yet been recorded. While the date of construction and actual usage is unknown, it appears to have been last set up during the 1960s as a Cold War fallout shelter. It includes small supply rooms still containing U.S. Department of Defense fallout shelter supplies and water rations from 1964. The walls and ceiling are constructed of massively thick concrete, and there are minimal lighting fixtures. It is very different from steam tunnel construction. More of this type of tunnel may exist in the downtown area. Another non-steam tunnel was discovered and documented in the basement of the historic Missoula Mercantile.


Supplies from the Department of Defense for 1960s Cold-War fallout shelters. Photo: Author’s Collection, 2013.


Another non-steam tunnel located in the basement of a building. Photo: Author’s Collection, 2013.

Basement spaces are any subterranean spaces containing archaeological and architectural features, particularly those that connect to steam tunnels, sidewalk voids and/or where arched or non-arched doorways “to no where” have been found. Basement spaces are located under most businesses in the downtown Missoula area. While the basement spaces themselves are not unusual, particularly in an urban business district, the features consistently found within them are of interest, including those with doorways that once led or still lead into rooms under the sidewalks and other unknown locations.


Sealed door and windows that once led to a now filled sidewalk void. Photo: Bethany Hauer, 2013.

These rooms under the sidewalks represent the fourth unit of analysis, sidewalk voids, sometimes referred to as sidewalk vaults. The voids are particularly significant, as they represent some of the more mundane realities (i.e. storage) of underground features that have somehow become rather sensationalized as opium dens and prostitution cribs. There is evidence, however, that some of these sidewalk voids contained small businesses and that some of the larger ones were at one time structurally connected from business to business within a city block. The bulk of sidewalk voids with doorways have been sealed; many of the voids themselves have been filled in for safety and structural reasons.


Example of one of the larger sidewalk voids seen so far. Photo: Bethany Hauer, 2013.

[i] Ann Felice Ramenofsky and Anastasia Steffen, Unit Issues in Archaeology: Measuring Time, Space, and Material (Salt Lake City: University of Utah Press, 1998).

All rights reserved. Reproduction or sharing of images on this site are strictly prohibited without written consent from the blog owner.