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Historical Maps Go Digital


Historical Maps Go Digital

In 1884, the second USGS Director John Wesley Powell briefed Congress on the need for a national mapping program, stating, “The map once constructed should be enduring…”   

In keeping with that spirit, The U.S. Geological Survey (USGS) has publicly released more than 161,000 digitally scanned historical maps spanning in excess of 130 years and covering the conterminous lower 48 states. This Historical Topographic Map Collection provides a comprehensive repository of the landscape of our Nation and tracks changes through time, providing essential clues critical in the understanding of our Nation’s topography, geography and development.  

“Just as parents might keep a photo album to record their children as they grew, these historical maps are the cartographer’s physical quantification of how the land changed as the Nation grew over the last 130 years,” explained USGS Director Marcia McNutt. “This historical collection contains immense scientific value as we shaped the land that shaped us.”  

With the recent completion of the states of Massachusetts and Florida, the Historical Topographic Map Collection can now offer, for free download, digital versions of the USGS legacy topographic map series which includes all scales and all editions originally published for the entire continental U.S.  

As chartered, the USGS topographic mapping program has accurately portrayed the complex geography of our nation through maps in the lithographic printed format. Since the official release  of the digital, scanned collection this past September, more than 1.2 million historical topographic maps have been downloaded from the website– an average of more than 5,700 maps per day. 

These chronological historical maps are an important national resource as they provide the long-term record and documentation of the natural, physical and cultural landscape. The history documented by this collection and the analysis of distribution and spatial patterns is invaluable throughout the sciences and non-science disciplines. Genealogists, historians, anthropologists, archeologists and others can use this collection for research as well as a framework on which a myriad of information can be presented in relation to the national landscape.  

The maps are offered to the public at no cost in GeoPDF format or as a printed copy for plus a handling charge from the USGS Store and can be used in conjunction with the new USGS digital topographic map, the US Topo.  

Similar historical maps for Alaska, Hawaii, Puerto Rico, the Virgin Islands and Pacific Territories will be available later this summer.

Collection website.


The project is part of the USGS National Geospatial Program (NGP) continuing efforts to support the mapping and location-based data needs of the Nation.  Visit nationalmap.gov, and follow us on Twitter @USGSTNM and our other social media channels.

USGS Newsroom


More information

Parameter Value Description
Magnitude mb The magnitude for the event.
Longitude ° East Decimal degrees longitude. Negative values for western longitudes.
Latitude ° North Decimal degrees latitude. Negative values for southern latitudes.
Depth km Depth of the event in kilometers.
Place Textual description of named geographic region near to the event. This may be a city name, or a Flinn-Engdahl Region name.
Time 1970-01-01 00:00:00 Time when the event occurred. UTC/GMT
Updated 1970-01-01 00:00:00 Time when the event was most recently updated. UTC/GMT
Timezone offset Timezone offset from UTC in minutes at the event epicenter.
Felt The total number of felt reports
CDI The maximum reported intensity for the event.
MMI The maximum estimated instrumental intensity for the event.
Alert Level The alert level from the PAGER earthquake impact scale. Green, Yellow, Orange or Red.
Review Status Indicates whether the event has been reviewed by a human.
Tsunami This flag is set to "1" for large events in oceanic regions and "0" otherwise. The existence or value of this flag does not indicate if a tsunami actually did or will exist.
SIG A number describing how significant the event is. Larger numbers indicate a more significant event.
Network The ID of a data contributor. Identifies the network considered to be the preferred source of information for this event.
Sources A comma-separated list of network contributors.
Number of Stations Used The total number of Number of seismic stations which reported P- and S-arrival times for this earthquake.
Horizontal Distance Horizontal distance from the epicenter to the nearest station (in degrees).
Root Mean Square sec The root-mean-square (RMS) travel time residual, in sec, using all weights.
Azimuthal Gap The largest azimuthal gap between azimuthally adjacent stations (in degrees).
Magnitude Type The method or algorithm used to calculate the preferred magnitude for the event.
Event Type Type of seismic event.
Event ID Id of event.
Event Code An identifying code assigned by, and unique from, the corresponding source for the event.
Event IDS A comma-separated list of event ids that are associated to an event.

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