William Cullen was a U.S. Representative

United States House of Representatives

The United States House of Representatives is one of the two Houses of the United States Congress, the bicameral legislature which also includes the Senate.The composition and powers of the House are established in Article One of the Constitution...

 from Illinois

Illinois

Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

.

Born in County Donegal, Ireland, Cullen immigrated to the United States in 1832 with his parents, who settled in Pittsburgh, Pennsylvania

Pittsburgh, Pennsylvania

Pittsburgh is the second-largest city in the US Commonwealth of Pennsylvania and the county seat of Allegheny County. Regionally, it anchors the largest urban area of Appalachia and the Ohio River Valley, and nationally, it is the 22nd-largest urban area in the United States...

.
He attended the public schools and the Allegheny Academy at Pittsburgh.
He moved to Adams Township, LaSalle County, Illinois, in 1846 and engaged in agricultural pursuits.
Sheriff of LaSalle County, Illinois in 1864 and 1865.
He moved to Ottawa, Illinois

Ottawa, Illinois

Ottawa is a city located at the confluence of the Illinois River and Fox River in LaSalle County, Illinois, USA. As of the 2010 census, the city population was 18,786...

, in 1865.
Political editor of the Ottawa Republican 1871-1887.

Cullen was elected as a Republican

Republican Party (United States)

The Republican Party is one of the two major contemporary political parties in the United States, along with the Democratic Party. Founded by anti-slavery expansion activists in 1854, it is often called the GOP . The party's platform generally reflects American conservatism in the U.S...

 to the Forty-seventh

47th United States Congress

The Forty-seventh United States Congress was a meeting of the legislative branch of the United States federal government, consisting of the United States Senate and the United States House of Representatives. It met in Washington, D.C. from March 4, 1881 to March 4, 1883, during the administration...

 and Forty-eighth

48th United States Congress

The Forty-eighth United States Congress was a meeting of the legislative branch of the United States federal government, consisting of the United States Senate and the United States House of Representatives. It met in Washington, D.C. from March 4, 1883 to March 4, 1885, during the last two years...

 Congresses (March 4, 1881-March 3, 1885).
He was an unsuccessful candidate for renomination in 1884.
He lived in retirement in Ottawa, Illinois

Ottawa, Illinois

Ottawa is a city located at the confluence of the Illinois River and Fox River in LaSalle County, Illinois, USA. As of the 2010 census, the city population was 18,786...

, until his death there January 17, 1914.
He was interred in Ottawa Avenue Cemetery.