William Williams Chapman (August 11, 1808 – October 18, 1892) was an American politician and lawyer in Oregon and Iowa. In Iowa he served in the United States House of Representatives when it was still the Iowa Territory and as United States Attorney when it was still part of the Wisconsin Territory. The Virginia native was also a member of Iowa’s Constitutional Convention before he immigrated to the Oregon Country in 1847. The next year part of the region became the Oregon Territory and Chapman would serve in the Oregon Territorial Legislature in 1849. After settling in Portland he helped to found The Oregonian newspaper and promote economic interests in the city while practicing law. He also was involved with building Canyon Road near Portland, dabbled in cattle ranching, and fought in the Rogue River War in Southern Oregon. In later years he served in the Oregon Legislative Assembly and promoted the expansion of railroads from Portland and promoted maritime trade in the city. A park, Chapman Square, in downtown Portland is named for him and was built on land he sold to the city. Chapman school is also named in his honor.