In 1879, the United States Geological Survey (USGS) assumed responsibility for mapping the country and produced its first topographic map.
Topographic maps are beneficial tools for analyzing the earth's surface, geographic planning and architecture, mining projects and recreational uses, such as camping and fishing.
Topographers had to carefully plot maps by hand until the 1940s, when aerial photography was introduced.
From 1879 until 1992, the USGS produced a large-scale topographic map series of the 48 contiguous states and Hawaii. It includes more than 54,000 maps, and identifies almost 2 million natural and manmade features.
Creating an accurate topographic map is a long process. It can take five years from start (identification of map features) to finish (printing).