HOSPSTCO indicates the five-digit state and county modified FIPS code listed for that hospital in the American Hospital Association Annual Survey of Hospitals. Each hospital has only one unique state/county code. If multiple hospital units are in different counties, HOSPSTCO is the county code of the primary facility (as indicated by American Hospital Association Annual Survey information).

HOSPSTCO can be used to link HCUP data to any other data set that uses the modified FIPS county code. The modified FIPS county code uses one county code for these independent cities and the surrounding county. For example, Baltimore City is included in Baltimore County; St. Louis City is included in St. Louis County; the independent cities of Virginia are included in the contiguous counties; and Kalawao county, Hawaii, is included in Maui County. The four Alaska Judicial Divisions are used as counties.

HOSPSTCO differs from the HCUP data element HFIPSSTCO. HOSPSTCO contains the modified FIPS county code. HFIPSSTCO contains the unmodified FIPS county code. The unmodified FIPS county code will include unique values for independent cities, such as Baltimore City and St. Louis City.

HOSPSTCO is missing if the data source that contributed discharge data to the NIS prohibits the release of hospital identifiers.