The United States' largest water, earth, and biological science and civilian mapping agency, the U.S. Geological Survey (USGS) (organized in 1879) is celebrating the 125th anniversary of its national program for topographic maps (1884�2009). More than 55,000 7.5-minute, 1:24,000-scale topographic maps were compiled and published by USGS in the 20th century, culminating in complete coverage of the contiguous 48 states in 1991. Together with the rise of the digital age and the explosion of Internet-based technologies, GIS technology has transformed topographic mapping science, enabling the electronic construct of the National Map of today. In offering the public an immense, authoritative resource for place-based analysis; diverse customization; and broad distribution of geographic information, the National Map has become the people's map. To help mark the celebration, ArcNews will highlight the USGS and some of its successes in this and upcoming 2009 issues. (See GIS Hero article and "GIS Versus the Volcano".)