At the corner of Rhein and Mittelstraße stands the Baroque house that housed the Neuwied customs office until the 1960s. Built in 1696, the house stands out externally with its high, curved decorative gables and numerous double windows, but also internally with its castle-like thick walls, heavy beams, vaults, and spiral staircase, in contrast to the generally lighter constructed half-timbered houses of the townspeople. It was probably built by the count's government after the city's pillaging in 1694 on the site of an older house that had been burnt down, and was used as a salt magazine, as evidenced by the salt-infused wall stones and the beams inside still containing salt. As the sovereign, the count held the salt monopoly. In the house, located near the Rhine, the salt cargo imported by ship was cleared through customs, stored, and sold at a fixed price with tax markup. In 1827, the Prussian state converted the former count's salt customs and storage house into the general main customs office, which has been the customs office for the southern part of the Neuwied district since 1925; traffic congestion in the old town and the shift of customs liable goods from ship to road and rail necessitated the relocation of the customs office in 1969.

Today, it is home to the gastronomy.