Portland, Oregon is 50% larger than Milwaukee.
Area: 251 km2 calculated
Milwaukee is the largest city in the U.S. state of Wisconsin, the 30th most populous city in the United States, and 39th most populous region in the United States. It is the county seat of Milwaukee County and is located on the southwestern shore of Lake Michigan. Wikipedia
Area: 376 km2 calculated
Portland is the largest city by population in the U.S. state of Oregon, near the confluence of the Willamette and Columbia rivers. Wikipedia