Log In

USGS Quad Map Grids

Pasadena Quad

These datasets contain the geographic extent of USGS 1:24,000 topographic maps (7.5- by 7.5-minute quadrangles).

Data Downloads

LA County: This dataset is optimized for LA County – some quad sheets are actually extended beyond the cord grid system to cover small areas of coastline.

Click here to download the LA County Quad Grid

United States: This dataset provides quadrangle name, identification number, publication data, and map coverage by state for each quadrangle.

Click here to download the US Quad Grid

What is a Quad Map (USGS Quadrangle Map)?

From our site: http://egis3.lacounty.gov/dataportal/2012/06/08/us-geological-survey-usgs-topographic-maps/ 

From Wikipedia: The US Geological Survey (USGS) produces several national series of topographic maps which vary in scale and extent, with some wide gaps in coverage, notably the complete absence of 1:50,000 scale topographic maps or their equivalent. The largest (both in terms of scale and quantity) and best-known topographic series is the 7.5-minute, 1:24,000 scale, quadrangle, a non-metric scale virtually unique to the United States. Each of these maps covers an area bounded by two lines of latitude and two lines of longitude spaced 7.5 minutes apart. Nearly 57,000 individual maps in this series cover the 48 contiguous states, Hawaii, U.S. territories, and areas of Alaska near Anchorage, Fairbanks, and Prudhoe Bay. The area covered by each map varies with the latitude of its represented location due to convergence of the meridians. At lower latitudes, near 30° north, a 7.5-minute quadrangle contains an area of about 64 square miles (166 km2). At 49° north latitude, 49 square miles (127 km2) are contained within a quadrangle of that size. As a unique non-metric map scale, the 1:24,000 scale naturally requires a separate and specialized romer scale for plotting map positions.[23] In recent years, budget constraints have forced the USGS to rely on donations of time by civilian volunteers in an attempt to update its 7.5-minute topographic map series, and USGS stated outright in 2000 that the program was to be phased out in favor of The National Map[24] (not to be confused with the National Atlas of the United States produced by the Department of the Interior, one of whose bureaus is USGS).

Using GIS Data on this site

GIS Data downloaded from this site generally requires GIS software to view. Click here for a list of GIS Data Viewers

GIS data available on this website is provided AS IS - please read the GIS Data Portal Terms of Use

Data Field Descriptions

Field in parenthesis are for LA County

QUAD_NAME (NAME_24K): Quad Map NAme
USGS_QD_ID (OHIO_INDEX): Quad Map Index
DATE_REV: Date Revised
DATE_PUB: Original Publication Date


GIS Source Information
Database Name: eGIS_Basemaps_Grids
Feature Class Name: USGS_1_24K_QUADRANGLE_MAP_GRID, USGS_1_24K_QUADRANGLE_MAP_GRID_US
Feature Dataset Name (if applicable):
Reference Date: Various
Accuracy: Other
Update Frequency: Other
Access Constraints:None

Contact Information
US Geological Survey








Leave a Reply