The Invsplit program splits an IDA, SMOKE ORL, or EMS-95 raw inventory file into multiple raw inventory files, based on the state codes (the first two digits of the state/county codes in the IDA files). The number of output files is set at run time based on the input file that defines the splitting. Up to 80 new files can be created from a single IDA inventory file, which is more than enough files to split a U.S. inventory into a separate file for each state. The program works on area, on-road mobile, nonroad mobile, and point inventories. Separating a single inventory file into multiple files allows the inventory data to be recombined with other data more easily.