The MIGRATE1 variable is an person-level variable that identifies if a person lived in the “same house” or a “different house” since a year ago. If the person indicates moving, information contained in MIGPLAC1 details whether a person moved between states, within the same state, or from abroad. Therefore this variable represents in-flow into the current residence. For out-flow information by PUMA see MIGPUMA1, which identifies the PUMA of residence 1 year ago for person records. Note that this variable is currently only available back until 2005.
Additionally, it sounds like you are looking for aggregated data, if so, you may want to check out IPUMS-NHGIS which provides aggregated data along with geographic boundary files for many topics including migration.
I hope this helps.