The USGS Geomagnetism Program operates a network of magnetic observatories that collect vector and scalar magnetometer data for use in Earth main-field modeling, geophysics research, space physics research, and space weather hazard assessment and mitigation. Until mid-2011, only 1-minute time resolution magnetic field measurements were archived with the INTERMAGNET consortium following international magnetic observatory standards. 1-second time resolution magnetic field measurements, which had already been collected by all the USGS observatories for up to almost a decade prior, started being archived with INTERMAGNET on June 13, 2011, or July 27, 2012 in the case of the more recently constructed Deadhorse (DED) magnetic observatory. This data release contains 1-second time resolution magnetic field measurements collected up through the end of 2012, after which time 1-second data from USGS magnetic observatories may be obtained from INTERMAGNET. There is some overlap between data in this release and those data archived with INTERMAGNET. Any discrepancies that may exist between these two data sources should resolve in favor of INTERMAGNET. CMO-specific notes: - there are significant gaps in the 2004 data, most notably in April - some filenames originally and mistakenly identified the College observatory as "COL", not "CMO". - some filenames originally possessing with a ".sec" extension were renamed to ".raw"