Julie Van Holland was the first customer to the new Post Office facility in the Sioux County community of Rock Valley, which opened its doors to the public at 8:30 a.m. on Monday, June 1, 1970. Construction on the $61,000 facility was finished a few days prior, nearly a year and a half after the construction contract was signed and over four years after the U.S. Postal Service formally announced Rock Valley would receive a new post office facility. The building was formally dedicated July 16, 1970.