Geosam is the Iowa Geological Survey's (IGS) geologic site and sample tracking program.  The long-term systematic collection and retention of earth science data continues to be of immeasurable value to the State of Iowa.  Refinements in data collection and interpretation have evolved with improved technology, and these refinements have permitted improved capabilities in problem-solving and service functions for the IGS to the general public.  Access to this data is instrumental in the production of most of the Survey’s geologic and hydrologic maps, reports, and responses to information requests.  Now that this information has been made available to everyone via the internet and the IGS homepage (, drillers, consultants, engineers, etc. can utilize this information to aid in estimating the depth, well construction concepts, and water yield of specific aquifers and other site specific design needs.  There are currently 77151 records in Geosam.  To view statistics of Geosam database - click here.

Disclaimer:  This electronic dataset was developed by staff of the Iowa Department of Natural Resources (IDNR), Geological Survey to carry out agency responsibilities related to management, protection, and development of the natural resources of Iowa.  Although efforts have been made to make it useful, IDNR assumes no responsibility for errors in the information.  Similarly IDNR assumes no responsibility for the consequences of inappropriate uses or interpretations of the data made by anyone to whom this data has been made available.  IDNR bears no responsibility to inform users of any changes made to this data.  Anyone using this data is advised that precision implied by the data may far exceed actual precision.  Comments on this data are invited and IDNR would appreciate that documented errors be brought to staff attention.  The development of this dataset represents a major investment of staff time and effort.  As a professional responsibility and courtesy, we expect that the Iowa Department of Natural Resources, Geological Survey will receive proper credit when this this dataset is utilized.

This information, related by a unique site identification number (wnumber), includes the owner name, county name, location (i.e. township, range, and section), well depth, and site type.  The database can be searched by location, county name, owner name, USGS 7.5' topographic quadrangle name, or any combination of these, or by wnumber.  For some sites, geology, water production, well casing, and a graphic representation of the site may be available.

The IGS Rock Library, located on the University of Iowa Oakdale Campus, contains rock samples that have been collected and studied almost continuously since 1933.   In 1993 it was calculated that it would cost over $93 million to commercially drill and recollect the cutting samples reposited in the library today. Preparation and study of these samples would cost an additional $6.5 million. To drill the core samples in the rock library today would cost $10.3 million, with an additional $1.5 million required to prepare and study the cores. The total replacement value of the drill samples in the IGS Rock Library is over $111.3 million. This library represents an irreplaceable resource for the citizens of Iowa!

For a printable discussion/description of Geosam and the IGS Rock Library - Pdf

Iowa Geological Survey     109 Trowbridge Hall     Iowa City, IA 52242-1319     Phone: 1-319-335-1575     Fax: 1-319-335-2754