Geographic Information Systems and Science for Cancer Control



Health Service Areas (HSAs) were originally defined by the National Center for Health Statistics, part of the Centers for Disease Control and Prevention, to be a single county or cluster of contiguous counties which are relatively self-contained with respect to hospital care. For further information about their initial use, please visit the Atlas of United States Mortality.

These HSAs have been modified so that none of the HSAs cross state boundaries. These are referred to as HSAs (NCI Modified).

Click on an HSA in the interactive map (below) to see the counties contained in the HSA or visit the SEER documentation on HSAs for more information.

HSA interactive map:


The groups for the colors of the areas on the map are determined by using the all of the individual Health Service Areas (HSAs) for that cancer/sex combination over the entire 40 year time period (8 statistics per HSA for the 5 year maps and 4 statistics per HSA for the 10 year maps). The statistics are broken up into 9 groups so that each group has the approximately the same number of HSAs in it. The Animated Historical Cancer Atlas uses NCI Modified HSAs.

Diagram of how cutpoints are determined:

Diagram of cutpoints

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