Library: Maps and Posters

Tab category links to PDFs (and jpg, tif) and Google Maps of Guam’s terrain and water resources.

WERI, University of Guam
Siegrist, Reagan, Randall, and Jenson 2008 – Geologic Map Sections, Guam Mariana Islands (scan)
Siegrist et al. 2007 – Geologic Map of Agat Quadrangle, Guam
Siegrist et al. 2007 – Geologic Map of Apra Harbor Quadrangle, Guam
Siegrist et al. 2007 – Geologic Map of Dededo Quadrangle, Guam
Siegrist et al. 2007 – Geologic Map of Hagåtña Quadrangle, Guam
Siegrist et al. 2007 – Geologic Map of Inarajan Quadrangle, Guam
Siegrist et al. 2007 – Geologic Map of Merizo Quadrangle, Guam
Siegrist et al. 2007 – Geologic Map of Pati Point Quadrangle, Guam
Siegrist et al. 2007 – Geologic Map of Ritidian Point Quadrangle, Guam
Siegrist et al. 2007 – Geologic Map of Talofofo Quadrangle, Guam
Siegrist et al. 2008 – Generalized Geology of Guam, Mariana Islands (Stratigraph Map)
Siegrist et al. 2008 – Composite Stratigraphic Sections (use with Stratigraph Map)

These geologic maps are also available at WERI’s website >>

Geologic Map Supplimentary Files:
Geologic Formations of High Islands on the Philippine Sea Plate (Stratigraph Chronology)


US Department of Interior, Geologic Survey, and NOS/NOAA, in cooperation with the Government of Guam
Tracey et al. 1964 – Geologic Map Sections Guam Mariana Islands, Professional Paper 403
Tracey et al. 1964 – Sample Locality Map of Guam, Mariana Islands, Professional Paper 403-A Plate 2

1968 – Agat, Guam, Quadrangle
1968 – Apra Harbor, Guam, Quadrangle
1968 – Dededo, Guam, Quadrangle
1968 – Inarajan, Guam, Quadrangle
1968 – Inarajan, Guam, Quadrangle, Mylar
1968 – Merizo, Guam, Quadrangle
1968 – Merizo, Guam, Quadrangle, Mylar
1975 (68) – Agana, Guam, Quadrangle
1975 (68) – Agana, Guam, Quadrangle, Mylar
1975 (68) – Agat, Guam, Quadrangle, Mylar
1975 (68) – Apra Harbor, Guam, Quadrangle, Mylar
1975 (68) – Pati Pont, Guam, Quadrangle
1975 (68) – Pati Pont, Guam, Quadrangle, Mylar
1975 (68) – Ritidian Point, Guam, Quadrangle
1975 (68) – Ritidian Point, Guam, Quadrangle, Mylar
1975 (68) – Talofofo, Guam, Quadrangle, Mylar

USGS Maps – USGS Topographic Maps    USGS Geologic Maps   USGS GIS Data

US Department of Agriculture, Soil Conservation Service, University of Guam, Government of Guam, Department of Commerce
USDA et al. 1985 – General Soil Map Territory of Guam

WERI UOG
Vann et al. 2017 – The Northern Guam Lens Aquifer
Vann et al. 2001 – Revised Topographic Volcanic Basement

WERI Collection
Mink 1992 – Plate 1, Volcanic Basement Contour Map

Borehole Database (site)
One Guam Aquifer Monitoring Program (Google Maps)     Observation Wells Plus (Google Maps)

Guam Waterworks Authority (Guam Production Wells and Borehole Database)
Production well status

Guam Environmental Protection Agency

Courtesy of Northern Guam Soil and Water Conservation District (NGSWCD, Joseph Santos) and Guam Department of Land Management (DLM)

An excellent resource for historical reference and determining use of Guamanian name places

Georeferenced Historic Maps for GIS, compressed (zip file)

1819: La De Freycinet – ESSAI, sur la géographic ancienne, DE L’ÎLE GWAM, Capitale des Îles Mariannes
1852: Coello – Guajan. Los nombres encerrados en parentesio corresponden å lugares antiguos, hoy dia despoblados
1852: Coello – Bahia Y Ciudad de Agaña, 1/20,000, Islas Meiacosxima

1900: Wheeler – Guam or Guajan Island, Exhibit A.
1902: L.M. Cox (CEC USN) – Island of Guam, 1:124,000
1913-1914: Strudevant et al. (Corps of Engineers) North Portion (Sheet 1 of 4), 1:25,000
1913-1914: Strudevant et al. (Corps of Engineers) North Central Portion (Sheet 2 of 4), 1:25,000
1913-1914: Strudevant et al. (Corps of Engineers) South Central Portion (Sheet 3 of 4), 1:25,000

1913-1914: 
Strudevant et al. (Corps of Engineers) South Portion (Sheet 4 of 4), 1:25,000
1915: city of Agana ~1915~, 1″ = 150′
1938: Fig. 118. Apra harbour, Guam, From lines are approximately 200-ft. intervals. Based on official sources
1939: Special Military Map of  Island of Guam, War Plans Section, Marine Barracks, Quantico, Wa., 1:60,000
1944: Army Map Service (AMS), 2nd Edition, Map of Guam Island, US Army, Washington DC
1942: Corps of Engineers (COE) Island of Guam (Uruno Point, Sheet 1 of 11) 1:20,000
1942: Corps of Engineers (COE) (1922 and 1942) Island of Guam (Ritidian Point, Sheet 2 of 11) 1:20,000
1942: Corps of Engineers (COE) (1922 and 1942) Island of Guam (Tumon Bay, Sheet 3 of 11) 1:20,000
1942: Corps of Engineers (COE) (1922 and 1942) Island of Guam (Apra Harbor, Sheet 5 of 11) 1:20,000
1942: Corps of Engineers (COE) (1922 and 1942) Island of Guam (Agana Bay, Sheet 6 of 11) 1:20,000
1942: Corps of Engineers (COE) (1922 and 1942) Island of Guam (Agana Bay, Sheet 6 of 11, v2) 1:20,000
1942: Corps of Engineers (COE) (1922 and 1942) Island of Guam (Pagat Point, Sheet 7 of 11) 1:20,000
1942: Corps of Engineers (COE) (1922 and 1942) Island of Guam (Agat Bay, Sheet 8 of 11) 1:20,000
1942: Corps of Engineers (COE) (1922 and 1942) Island of Guam (Agat Bay, Sheet 8 of 11, v2) 1:20,000
1942: Corps of Engineers (COE) (1922 and 1942) Island of Guam (Talofofo Bay, Sheet 9 of 11) 1:20,000
1942: Corps of Engineers (COE) (1922 and 1942) Island of Guam (Port Merizo, Sheet 10 of 11) 1:20,000
1942: Corps of Engineers (COE) (1922 and 1942) Island of Guam (Port Inarajan, Sheet 11 of 11) 1:20,000
1944: Army Map Service (AMS), 2nd Edition, Map of Guam Island, US Army, Washington DC
1954: AMS (AFFE) Edition 1 Guam

1984: Chase et al., Marine Physiography of the Commonwealth of the Northern Mariana Islands, Department of Interior, US Geological Surve