![](https://cdn.firespring.com/images/72e9530f-b598-4ff2-accc-5e47b192890f.png)
For the Topo Map in the Masthead:
U.S. Geological Survey, 2023, topoView—A USGS topographic map viewer and data download application : U.S. Geological Survey National Geologic Map Database website, accessed [date] at https://ngmdb.usgs.gov/topoview/.