[8] The Jay County Courthouse, Portland Commercial Historic District, and Jonas Votaw House are listed on the National Register of Historic Places.

[9] According to the U.S. Census Bureau, Portland has a total area of 4.97 square miles (12.88 km2), of which 1.6 acres (6,524 m2), or 0.05%, are water.

[10] The Salamonie River runs through the city just south of its center.

At the 2010 census there were 6,223 people, 2,607 households, and 1,620 families living in the city.

There were 3,005 housing units at an average density of 646.2 per square mile (249.5/km2).