The 28 lock and dams sites on the upper Mississippi River is currently central to transporting U.S. agricultural commodities to the world market. This aging lock and dam system and slow double lockage process at the 600-foot locks have generated concern about its navigational efficiency. The objective of this study is to examine the determinants of delay occurred at the lock and dam system on the River. The focus is on the impact of lockage processing time (lock capacity issue) and unscheduled outages/stalls (system management issue) on lock delay. Results suggest that reduction in processing time reduces lock delay considerably. In addition, increases in the number of unscheduled outage cause by weather issue result in more delay hours. Delays at a given lock is also affected by lockage duration, the average duration of unscheduled stalls caused by weather, the unscheduled outage related to the occurrence of mechanical and vessel issues at nearby locks.