The first post office in the Jasper County seat of Newton was established in 1847, one year after the new county was commissioned. City delivery was established in 1899, with rural delivery from the Newton Post Office beginning in 1907. After a number of locations, including a rented building which was condemned in the early part of the twentieth century, the current facility was constructed in 1970.

Featuring a large loading platform and truck bed level, the one-story brick building contained over 21,000 square feet of space. The building may have been too big and too soon, as mail that was previously sorted in Newton was redirected to Des Moines around this time. Postal workers employed at the Newton location declined from 50 to 40 within a few years of opening the new building.