James Boulden the Elder and his family moved to Delaware from Maryland in the mid-18th century, amassing wealth and expanding their land ownership in Pencader Hundred as the century progressed. The two-story brick mansion house was built during this time period and is a strong representation of Georgian architecture. A service wing erected between 1800-1820 was added to the main structure and is a rare example of stone construction in this area. Five outbuildings situated on the property include a corncrib/granary, a smoke house, a dairy barn and stable, a milk house, and an open frame shed for cattle. In the 1820s, son James ran a diversified farming operation; growing corn, wheat and hay; raising cattle for beef and dairy; using houses and oxen to work the fields; and producing wool from sheep. During the 19th century the farm increasingly focused on dairying, producing milk and butter for the Mid-Atlantic urban markets. After son James' passing in 1826, the farm was left to his grate-nephew and namesake. Circa 1850, James Boulden III carried out substantial renovations to the mansion house incorporating several "Revival" styles, evident in the ornate woodwork and a reorganization of the interior space. The farm remained in the hands of the Boulden family and their descendants until 1918, when the sale of the property ended their 175-year ownership. The architectural and agricultural importance of Poplar Hall was recognized when the property was named to the National Register of Historic Places on January 26, 1988.