The Sioux City mail processing center has closed despite attempts to save it.
The final pieces of mail went through the center on Saturday morning. Operations are being transferred to a processing center in Sioux Falls, S.D.
The postal service announced the consolidation decision in June as part of its plan to cut its staggering losses. Iowa's congressional delegation and others tried to fight the closure.
Postal officials have said local mail delivery will not be affected by the move. However, Sioux City will lose about 70 jobs.