William Hyser (1826-1909), a pioneer surgeon and Civil War captain, came to Plainfield Township in 1850 when it was a lumber center. In 1852 he built a Greek Revival house as a home and office for his medical and civic duties. At various times he served as township clerk, school inspector and supervisor, and justice of the peace. The house also served as a stagecoach station and a post office. Plainfield was first settled in 1838, and its post office, known as the Austerlitz office because there was a Plainfield post office elsewhere, was established in 1843. It was later housed in this structure for a short time. Mail first came by horse, then by stagecoach in 1848, and by rail via nearby Belmont in 1876. Before envelopes, letters were folded and closed by sealing wax and other means. The Austerlitz office operated until 1913, when it was consolidated into the one at Belmont. In 1976 the house was moved to its present site. The only remaining structure from the original Plainfield village, it is now restored as a museum.